I can't say I've played one, but I did see a short clip of a demo. Looked pretty cool. Reminded me of 80's new wave music, especially when I remember those guitar shaped keyboards. (Sometimes I think it might be a good thing that I'm too young to remember much of the '80s.)
Anyway, I found
this for the iGuitar. Kind of pricey. I also found
this about MIDI guitars. It looks to have a lot of information.