AmpliTube is a very cool software based Guitar and Bass tone-creation solution. I own and use AmpliTude 3 on my computers and also have the AmpliTube for iPhone and iPad. Using iRig Stomp is a great way to use AmpliTube running on your iPhone or iPad on your pedalboard.

IK Multimedia iRig STOMP is the first stompbox guitar interface for iPhone, iPod touch and iPad. For the first time, guitar and bass players can now integrate their favorite iOS signal processing apps into their existing live pedalboard setup for enhanced tone shaping and effects processing using an iPhone/iPod touch or iPad.