Post Via Email to a Custom Post Type

When a post is submitted by email and published WordPress Runs an action hook named 'publish_phone' so you can get the post there and change its type like this:

add_action('publish_phone','custom_type_by_mail');
function custom_type_by_mail($post_id){
    $p = get_post($post_id,'ARRAY_A');
    $p['post_type'] = "YOUR_CUSTOM_TYPE_NAME_HERE";
    wp_update_post($p);
}

Probably not the smartest way but it does work and its simple.