Magento Snippet - Set the Catalog Product Grid column count

local.xml

<?xml version="1.0" encoding="UTF-8"?>
<layout>
    <catalog_category_default translate="label">
        <reference name="content">
            <block type="catalog/category_view" name="category.products" template="catalog/category/view.phtml">
                <block type="catalog/product_list" name="product_list" template="catalog/product/list.phtml">
                    <action method="setColumnCount"><columns>4</columns></action>
                </block>
            </block>
        </reference>
    </catalog_category_default>
	
    <catalog_category_layered translate="label">
        <reference name="content">
            <block type="catalog/category_view" name="category.products" template="catalog/category/view.phtml">
                <block type="catalog/product_list" name="product_list" template="catalog/product/list.phtml">
                    <action method="setColumnCount"><columns>4</columns></action>
                </block>
            </block>
        </reference>
    </catalog_category_layered>
</layout>