This video, via thesoundtestroom, offers an unofficial ‘Beginners Guide To Audiobus’.
AudioBus is a tool and standard for routing audio between applications on IOS. For more info on AudioBus, see What Is Audiobus & How Will It Change Mobile Music Making?.
Probably not much news for die hard Synthtopia iOS users, but never less excellent tutorial for everyone else
Good demo! Check out our written guide for understanding audiobus: http://en.audiofanzine.com/getting-started/editorial/articles/understanding-audiobus.html