making urls clickable for wordpress custom post type field?

put this in your functions.php:

function my_format_artist_links($urls) {
    $urls = explode(',', $urls);
    $links = array();
    foreach ($urls as $url) {
        if (empty($url)) continue;
        $links[] = '<a href="http://'.$url.'">'.$url.'</a>';
    }
    return implode(',', $links);
}

and then replace

<p><span>Link(s):</span> <?=$artist_links?></p>

with

<p><span>Link(s):</span> <?php echo my_format_artists_links($artist_links); ?></p>'