attribute.php

<?php

/* @var $installer Mage_Catalog_Model_Resource_Eav_Mysql4_Setup */
$installer = $this;

$installer->startSetup();

// Add the attribute `baz` with some fields
$installer->addAttribute(Mage_Catalog_Model_Product::ENTITY, 'baz', array(
    'label' => 'The Baz', // The label ;)
    'group' => 'General', // The group (in the admin page)
    'input' => 'text', // Used for the input type
    'required' => true, // Is it required?
    //'source' => '', // Used for a source model
    //'backend' => '', // Used for a backend model (before and after save, before and after load of the product)
    //'frontend' => '', // Used for a frontend model (like the image frontend model with the getUrl method)
    //'class' => '', // Used for a backend HTML class (usefull for javascript validation – with the 'validate-email' class for example)
    'comparable' => false, // Comparable? (on front, via the comparable products).
    //'default' => '', // The default value
    'filterable' => false, // Filterable? (on front, in the category view or search)
    //'apply_to' => '', // Used for product type restrictions
    'global' => Mage_Catalog_Model_Resource_Eav_Attribute::SCOPE_STORE, // The scope
    'is_configurable' => false, // Is it a configurable attribute?
    'is_html_allowed_on_front' => false, // Is HTML allowed on front?
    //'note' => '', // Maybe a simple note below the input field in admin
    'searchable' => false, // Is it searchable?
    'sort_order' => '', // Which position on the admin page?
    'type' => 'varchar', // The attribute type (varchar, text, int...)
    'unique' => false, // Is it unique?
    'used_for_sort_by' => false, // Is it used for the 'sort by' select on a catalog/search page?
    'used_in_product_listing' => true, // In Flat?
    'user_defined' => false, // Is it user defined? If false the attribute isn't removable.
    'visible' => true, // Is it visible? If true the field appears in admin product page.
    'visible_on_front' => true, // Visible on front?
    'visible_in_advanced_search' => false, // Is it visible on advanced search?
    'wysiwyg_enabled' => false, // Is Wywiwyg enable? (use 'editor' input if you put true ;))
));

bad.xml

<?xml version="1.0" encoding="utf-8" ?>
<config>
    <!-- ... -->
    <global>
        <!-- ... -->
        <catalog>
            <product>
                <type>
                    <foo translate="label">
                        <label>Custom Foo Product Type</label>
                        <model>catalog/product_type_simple</model>
                        <composite>0</composite>
                        <index_priority>10</index_priority>
                    </foo>
                </type>
            </product>
        </catalog>
    </global>
</config>

eav_setup.php

<?php

class Mage_Eav_Model_Entity_Setup extends Mage_Core_Model_Resource_Setup
{
    
    /**
     * Mage_Core_Model_Resource_Setup
     */
    public function addConfigField($path, $label, array $data=array(), $default=null);
    public function afterApplyAllUpdates();
    public function applyDataUpdates();
    public function applyUpdates();
    public function callbackQueryHook(&$sql, &$bind);
    public function deleteConfigData($path, $scope = null);
    public function deleteTableRow($table, $idField, $id, $parentField = null, $parentId = 0);
    public function endSetup();
    public function getCallAfterApplyAllUpdates();
    public function getConnection();
    public function getFkName($priTableName, $priColumnName, $refTableName, $refColumnName);
    public function getIdxName($tableName, $fields, $indexType = '');
    public function getTable($tableName);
    public function getTableRow($table, $idField, $id, $field=null, $parentField=null, $parentId=0);
    public function run($sql);
    public function setConfigData($path, $value, $scope = 'default', $scopeId = 0, $inherit=0);
    public function setTable($tableName, $realTableName);
    public function startSetup();
    public function tableExists($table);
    public function updateTable($table, $conditionExpr, $valueExpr);
    public function updateTableRow($table, $idField, $id, $field, $value = null, $parentField = null, $parentId = 0);

    /**
     * Mage_Eav_Model_Entity_Setup
     */
    public function addAttribute($entityTypeId, $code, array $attr);
    public function addAttributeGroup($entityTypeId, $setId, $name, $sortOrder = null);
    public function addAttributeOption($option);
    public function addAttributeSet($entityTypeId, $name, $sortOrder = null);
    public function addAttributeToGroup($entityType, $setId, $groupId, $attributeId, $sortOrder = null);
    public function addAttributeToSet($entityTypeId, $setId, $groupId, $attributeId, $sortOrder=null);
    public function addEntityType($code, array $params);
    public function cleanCache();
    public function createEntityTables($baseTableName, array $options = array());
    public function getAllAttributeSetIds($entityTypeId = null);
    public function getAttribute($entityTypeId, $id, $field = null);
    public function getAttributeGroup($entityTypeId, $setId, $id, $field = null);
    public function getAttributeGroupId($entityTypeId, $setId, $groupId);
    public function getAttributeGroupSortOrder($entityTypeId, $setId, $sortOrder = null);
    public function getAttributeId($entityTypeId, $id);
    public function getAttributeSet($entityTypeId, $id, $field = null);
    public function getAttributeSetId($entityTypeId, $setId);
    public function getAttributeSetSortOrder($entityTypeId, $sortOrder = null);
    public function getAttributeSortOrder($entityTypeId, $setId, $groupId, $sortOrder = null);
    public function getAttributeTable($entityTypeId, $id);
    public function getDefaultAttributeGroupId($entityType, $attributeSetId = null);
    public function getDefaultAttributeSetId($entityType);
    public function getEntityType($id, $field = null);
    public function getEntityTypeId($entityTypeId);
    public function installDefaultGroupIds();
    public function installEntities($entities = null);
    public function removeAttribute($entityTypeId, $code);
    public function removeAttributeGroup($entityTypeId, $setId, $id);
    public function removeAttributeSet($entityTypeId, $id);
    public function removeEntityType($id);
    public function setDefaultSetToEntityType($entityType, $attributeSet = 'Default');
    public function updateAttribute($entityTypeId, $id, $field, $value = null, $sortOrder = null);
    public function updateAttributeGroup($entityTypeId, $setId, $id, $field, $value = null);
    public function updateAttributeSet($entityTypeId, $id, $field, $value = null);
    public function updateEntityType($code, $field, $value = null);

}

good.xml

<?xml version="1.0" encoding="utf-8" ?>
<config>
    <!-- ... -->
    <global>
        <!-- ... -->
        <catalog>
            <product>
                <type>
                    <foo translate="label">
                        <label>Custom Foo Product Type</label>
                        <model>jbh_catalog/product_type_foo</model>
                        <price_model>jbh_catalog/product_type_foo_price</price_model>
                        <composite>0</composite>
                        <index_priority>10</index_priority>
                        <price_indexer>jbh_catalog/product_indexer_price_foo</price_indexer>
                        <index_data_retreiver>jbh_catalog/catalogIndex_data_foo</index_data_retreiver>
                    </foo>
                </type>
            </product>
        </catalog>
    </global>
</config>

indexer.php

<?php

class Jbh_Catalog_Model_Resource_Product_Indexer_Price_Foo extends Mage_Catalog_Model_Resource_Product_Indexer_Price_Default
{}

layout.xml

<PRODUCT_TYPE_foo translate="label" module="catalog">
    <label>Catalog Product View (Foo)</label>
    <reference name="product.info">
        <block type="catalog/product_view_type_simple" name="product.info.foo" as="product_type_data" template="catalog/product/view/type/default.phtml">
            <block type="core/text_list" name="product.info.simple.extra" as="product_type_data_extra" translate="label">
                <label>Product Extra Info</label>
            </block>
        </block>
    </reference>
</PRODUCT_TYPE_foo>

price.php

<?php

class Jbh_Catalog_Model_Product_Type_Foo_Price extends Mage_Catalog_Model_Product_Type_Price
{}

retreiver.php

<?php

class Jbh_Catalog_Model_CatalogIndex_Data_Foo extends Mage_CatalogIndex_Model_Data_Simple
{

    /**
     * Retreive product type code
     * @return string
     */
    public function getTypeCode()
    {
        return Jbh_Catalog_Model_Product_Type_Foo::TYPE_CODE;
    }

}

set.php

<?php

/* @var $installer Mage_Catalog_Model_Resource_Eav_Mysql4_Setup */
$installer = $this;

// The Default attribute set
$defaultAttributeSetId = $installer->getAttributeSetId($installer->_defaultAttributeSetName);

// Add the new set
$newAttributeSetName = 'Bar';
$installer->addAttributeSet(Mage_Catalog_Model_Product::ENTITY, $newAttributeSetName);
$newAttributeSetId = $installer->getAttributeSetId(Mage_Catalog_Model_Product::ENTITY, $newAttributeSetName);
$model = Mage::getModel('eav/entity_attribute_set')->load($newAttributeSetId);
$model->initFromSkeleton($defaultAttributeSetId)->save();

// If you want a new group in your attribute set, use this :
//$newGroupName = 'Group Name';
//$installer->addAttributeGroup(Mage_Catalog_Model_Product::ENTITY, $newAttributeSetId, $newGroupName);

setup_price.php

<?php

/* @var $installer Mage_Catalog_Model_Resource_Eav_Mysql4_Setup */
$installer = $this;

$installer->startSetup();

$attributes = array(
    'price',
    'special_price',
    'special_from_date',
    'special_to_date',
    'minimal_price',
    'cost',
    'tier_price',
    'weight',
    'tax_class_id'
);

foreach ($attributes as $attribute) {        
    $applyTo = explode(',', $installer->getAttribute(Mage_Catalog_Model_Product::ENTITY, $attribute, 'apply_to'));
    if (!in_array('foo', $applyTo)) {
        $applyTo[] = 'foo';
        $installer->updateAttribute(Mage_Catalog_Model_Product::ENTITY, $attribute, 'apply_to', join(',', $applyTo));
    }
}

$installer->endSetup();

type.php

<?php

class Jbh_Catalog_Model_Product_Type_Foo extends Mage_Catalog_Model_Product_Type_Simple
{

    /**
     * Product type code
     * @const string
     */
    const TYPE_CODE = 'foo';

}