Hi all, (Yay first post!)

Has anyone done anything with the Arduino/USB Shield/iPhone combo?
Here's the shield I'm looking at:
SparkFun Electronics - USB Host Shield
I would like to adjust my iPhone with simple knobs and switches. For my application, the standard USB 30pin cable is best. I'd really rather not use serial.

So, my question is this: How do I receive data over the USB cable? (Jailbreaking is ok.)

Thanks so much!!!
- Loren