Forscore is the iPad's first musical score program. Sheet music was made for this.
Loopseque is an incredibly simple app for creating music. With Loopesque making music is like playing a game. Create beats and switch fast between patterns. You can access you music instantly and anywhere...Click Here to Buy Loopseque
Amplitube by IK multimedia is a killer app and gives you the ultimate guitar and bass multi-effect processor. Use the amplitube adaptor and you are ready to ROCK!!