If you are into playing the guitar or any other instrument that has a 1/4″ input on it, the StompBox from Griffin Technology will let you control the effects. The StompBox is an app and hardware combo that was announced a while back and is now finally shipping.
The StompBox will work with a guitar, bass, keyboard, or electric violin. I bet it would work with one of those 80’s hair band Keytar things too. The software portion is an app from Frontier Design called iShred LIVE that allows the effects to be created in real time. The hardware part is a foot switch.
The foot switch has four buttons and each button can be programmed to a single effect. Once programmed the player can change between those effects using their feet so their hands are on the instrument at all times. The StompBox ships with a 1-meter long cable for hooking the iPhone or iPad to the instrument along with headphones. You can order it now for $99.99 over at the Griffin Technology website.