i have just released an iOS guitar app, i'm pretty excited with how it's doing so far (a few hundred downloads since yesterday, with no advertising at all), i use it a lot, as you can imagine, the whole idea came from my own needs, and i think other people might find it useful too
the app is free and you can see a few screenshots here
http://itunes.apple.com/us/app/tabfinde ... &ls=1&mt=8
if you end up downloading and enjoying it, please take your time to rate it and review it. share it with your friends and etc.