Developer: Pandora Media, Inc.
Price: free Download on the App Store
When the Pandora music discovery service first appeared in 2004, I was fascinated with the product. Just type in the name (or part of the name) of your favorite band, and Pandora will create a custom "radio station" around that band, including songs from the band itself, as well as songs that "sound like" that artist. For example, if you type in "bob dylan", Pandora will start playing "Don't think twice" by Dylan, followed by "The Last Waltz" by The Band, followed by Neil Young. Its a phenomenal way to discover new music.
The big problem up until now was that to appreciate Pandora, you needed to listen to music on your computer. With the free Pandora App for iPhone last week, this just changed. Now, you can listen to your Pandora music channels right on your phone. Plug your phone into the audio jack on your home stereo and Pandora will act as a tireless (and incredibly relevant) DJ. Or with iTrip, or an mp3 jack adapter, you can easily listen to Pandora in your car.
Its hard to appreciate the power of the underlying technology unless your experience it for yourself. Now 4 years old, Pandora has mapped out most of the "musicsphere" with its proprietary "music genome" secret sauce. Type in just a part of any band, and Pandora will fill in the rest, and lead you to other very similar artists which you would probably never find out about otherwise.
Two additional features of the Pandora iPhone app deserve special praise. First of all, the bookmarking feature allows you to save future songs for reference while you are listening to a Pandora Mix. You can then use these songs as the departure points for other "stations", or directly access iTunes to buy them right from your iPhone. This second feature is so addicting that you may find yourself buying hundreds of new songs for your iTunes collection.