Apps for performing

[Chicken Chaser]

Someone showed me Yamaha's notestar all the other day which looked great. You can buy well known songs on there, and then remove vocals or instruments from the track allowing a full backing to the song. Great idea but iPad only and I'm on an android tablet!

I can read music so would appreciate some sheet music apps, or band accompanied apps which I can plug and play.

Any other apps which people could recommend would be greatly received! I'm playing Piano or guitar.