Today I read an email about using a USB to guitar cord and plugging in to the camera kit to get the guitar sound in to AmpliTube. After finding this thread I decided to try it with GarageBand. Earlier today I tested it out with AmpliTube.
I have an iRig. There is a little bit of hiss, but nothing to be afraid of. You can get them on the web for about fifteen dollars (US) including postage.
With the USB camera kit module I plugged in my guitar with the cord that comes with RockSmith for my Xbox. In AmpliTube it sounds off right away. In GarageBand you have to remember to turn on the "monitor" so you can hear the sounds. Turn up the Gain, Volume, and Master on the amp. To see the monitor selection you have to have your guitar plugged in and touch the icon that looks like a quart Eric inch jack on the upper left of the amp screen. If I remember right you can also see the jack icon when you are looking at the stomp boxes.
Sent from my iPad using iPF - Peace