I currently use http://www.albumreminder.com/ http://www.albumreminder.com/ for this. It imports your artists from last.fm or itunes, and provides you with an R

I currently use http://www.albumreminder.com/ http://www.albumreminder.com/ for this. It imports your artists from last.fm or itunes, and provides you with an RSS feed and/or email notifications of new artist releases.