I was most excited about the App Store that is opening at the same time on iTunes. Developers are now able to write software for the iPhone (and iPod Touch) and publish their work at iTunes. Some of these apps are free and some are low cost.
A quick look at iTunes this morning turned up an app that music teachers may be interested in. Guitar Toolkit looks like something that music teachers could use. A lot. Ever wish you had a tuner in your pocket? I probably wouldn't use it for the alternate guitar tunings, but just hearing a A=440 that is actually in tune would be helpful no matter what ensemble I am working with. This might be worth a closer look.
(Quick Edit-- I went back to the store and after playing around a little more. I found a NUMBER of other apps that may be a help to music teachers. Happy shopping.)
Guitar Toolkit must need the microphone from the phone, so I suppose my iPod won't run it. I wonder if the IRS will let me deduct my iPhone bill?