iTunes added a live search feature to the iTunes music store today. When you begin typing a menu appears to try and autocomplete your search keywords. The feature does seem to provide keywords for artists, albums and songs though there is no visual distinction between the keyword types. While this is a welcome addition, Yottamusic has had a similar feature now for months, and does show the distinction between keyword types.
iTunes Live Search:
Yottamusic Live Search: