Griffin is launching the US$79.99 GuitarConnect Pro (http://store.griffintechnology.com/guitarconnect-pro), which adds an instrument input to iPad and iPhone allowing users to gain an all-digital connection from guitars and other instruments directly into GarageBand and most Core Audio apps.
 
It adds a standard quarter-inch instrument jack with a built-in gain control to an iPad or iPhone. GuitarConnect Pro was created to turn iPad or iPhone into a compact performance or practice rig. A built-in gain control wheel allows the user to adjust the strength of the instrument’s input signal.

At one end, it has a quarter-inch mono jack to fit standard instrument cables. At the other end is a dock connecter for the iPad and iPhone. You can listen with speakers or headphones from the headphone jack of the iOS device.