Easiest way to obtain information about a youtube video afaik is to parse the string retrieved from: http://youtube.com/get_video_info?video_id=XXXXXXXX
Using something like PHP’s parse_str(), you can obtain a nice array of nearly anything about the video:
$content = file_get_contents("http://youtube.com/get_video_info?video_id=".$id);
parse_str($content, $ytarr);
echo $ytarr['title'];
That will print the title for the video using $id as the video’s id.