Playing instruments on a phone requires a different mindset considering the small screen and the difficulty to replicate the sounds using just a touch screen interface. Enterprising folks have rose up to the challenge with some great success like the Atomic Tom band and The Rend Collective Experiment, whereby iPhones loaded with different music apps, replaced physical instruments all together.
I was then pretty impressed when I came upon the Blues Box 2.0 app on YouTube by Mat Velloso. Here is how he describes it
Mat’s BluesBox v1.1 provides a fun and easy way of playing Blues with your Phone. Minimum music knowledge necessary and you can have the sensation of playing a bass or an electric guitar with or without your favourite song playing on the background. Try playing with a friend (i.e. a bass and a guitar) as well!
The thing I like about it most is that rather than trying to mimic guitar frets, He chose an interface which works well with a touch screen. The first version of the app was pretty bland but the second one has gotten the much needed polish and offers a free trial. It is still version 1.0 on the marketplace but hopefully that will soon change to the one demoed on the video . Now, I would like to see a video in which this app, together others are used to produce a B.B King like performance!