I've used mine quite a bit. Much faster finding tunes than rifling through even Pocket Changes much less a Real Book. The only drawback is sometimes other folks' amplifiers pick up that characteristic iphone interference. There's one pianist I play with occasionally that I can't use the phone with. His amp just screams whenever I pull the phone out. Another guitarist's amp makes noise but not quite as loud. My amp doesn't have this problem nor do the amps of a lot of the other guys I play with. It is a seriously cool toy.
mark
Don't you just hate that noise?
Have you tried using Airplane Mode? If you go to the Settings menu on the iPhone home screen, the first option is Airplane Mode. It turns off all radio transmissions so you should get no nasty interference.
Rick
