Here is a comment from the first youtube of pocketguitar that I saw, the first one I became aware of, as I'm on the tradlessons list and it was emailed to me.
http://www.youtube.com/watch?v=FJdVs1rEpK0

"tradlessons
It will do chords, but its a bit awkward to hold the phone and get all the the fingers down. Since there is no physical feedback, its pretty challenging to play with any sort of accuracy even for single note lines."