The kids at Potion Factory are at it again. Their latest gorgeous app is Tangerine. Tangerine scans your iTunes library (very quickly) and analyzes the beat intensity of your tracks so that you can create playlists based on the intensity of the music (i.e. fast paced songs for working out, and slower songs for when you are pitching woo).
At the moment the app is in beta, so it is free for download. If you blog about it you'll get a free license when the app is released.
Via Red Sweater Blog.