I am just like the PP - I got the wait time app and look at it all the time, even though I am in Ohio and my trip is not for over 3 months!!
For the poster who asked about the WDW apps, just go to the iTunes store and do a search for Disney World apps. There are quite a few out there, but make sure you investigate thoroughly (read detailed descriptions and reviews), especially before you buy any paid ones. Some of them look kind of useful, others either have issues or are superfluous, especially for those of us familiar with the parks.
I am considering the restaurant one, though, it looks as if it might be quite useful, and it's only .99.
What I love about the free wait time one is the way it works - people who have it are the ones who give the information, so it's always pretty current, and will only get more so as more people use it. So it's not based on info that they get from Disney, it is people walking around the parks and posting their wait times. The creators say it will always be done this way, so that it will always remain a free app. How cool is that?
For the iPhone/iPod Touch question, you can download any app onto your Touch, the question is whether it is useful without a wi-fi connection. For example, the ones that just have park maps might be fine, but I would think something like the wait time one would NOT be, because there is no Wi-Fi available in the parks, so the info would not be updated.
Sign me up for the iPhone fan club. It is insane what this little thing can do, it's like a sci-fi communicator or something. Love it, love it.