Convert tumblr v1 xml response to Octopress markdown. See gist 5023226 if you would like to convert body.html to markdown (pandoc required).

tumblr2markdown.php

<?php

$file  = './tumblr.xml';
$xml   = simplexml_load_file($file);
$posts = $xml->posts;
$root  = "./_posts";

if (!is_dir($root)) {
    mkdir($root);
}

foreach ($posts->post as $post) {
    $id   = (string)$post['id'];
    $url  = (string)$post['url-with-slug'];
    $date = (string)$post['date'];
    $slug = (string)$post['slug'];
    $dt   = new \DateTime($date);

    $tag = array();
    if (isset($post->tag)) {
        foreach ($post->tag as $t) {
            $tag[] = "$t";
        }
    }

    $titleVar = "regular-title";
    $title    = isset($post->$titleVar) ? $post->$titleVar : null;
    $title    = "$title";

    $bodyVar = "regular-body";
    $body    = isset($post->$bodyVar) ? $post->$bodyVar : null;
    $body    = "$body";

    $dir = $root . "/$id";
    if (!is_dir($dir)) {
        mkdir($dir);
    }

    $metaFile = sprintf("%s-%s.markdown", $dt->format('Y-m-d'), $slug);
    $meta = array(
        '---',
        'layout: post',
        sprintf('title: "%s"', $title),
        sprintf('date: %s', $dt->format('Y-m-d H:i')),
        'comments: false',
        sprintf('categories: [%s]', implode(', ', array_map(function($t){ return sprintf("'%s'", $t);}, $tag))),
        '---',
    );
    file_put_contents($dir . "/" . $metaFile, implode("\n", $meta) . "\n");

    $bodyFile = "body.html";
    file_put_contents($dir . "/" . $bodyFile, $body);
}