Add TinyMCE to CPT metaboxes in 3.1?

Use this class: http://www.deluxeblogtips.com/p/meta-box-script-for-wordpress.html

and then call the metabox like this (don’t forget to read the manual and view some examples):

$meta_boxes[] = array(
    'id' => 'textmetabox',
    'title' => 'Your Meta Box Title',
    'pages' => array('post', 'slider', 'whatever-your-cpt-is'),

    'fields' => array(
        array(
            'name' => 'Your thoughts about Deluxe Blog Tips',
            'id' => $prefix . 'thoughts',
            'type' => 'wysiwyg',
            'std' => '<b>It\'s great!</b>',
            'desc' => 'Do you think so?',
            'style' => 'width: 300px; height: 400px'
        )
    )
);