
MAKE announces the availability of the Redpark Breakout Pack for Arduino and iOS. This kit includes the only Apple-approved serial interface cable having a DB9 serial connector on one end and the iPhone connector on the other.
As MAKE describes it:
Exclusively in the Maker Shed, the Redpark Breakout Pack for Arduino and iOS makes interfacing your iPhone, iPad, or iPod touch with the real world easy! This bundle is known to work with Arduino and includes the Redpark Serial Cable for iOS, P4 Serial Breakout, and our Mintronics: Survival Pack. This is the development kit for the iPhone and iPad we have been waiting for!
Thanks Hoz, via the contact form.

This kit includes the only Apple-approved serial interface cable having a DB9 serial connector on one end and the iPhone connector on the other
What a joke, so without Apple-approved cable the only way is jailbreaking? Incredible…
I used buspirate, python and an iPad via serial port (500kOhm Accessory Indicator) to play with Accessory Protocol over serial port. You can see some photos here http://tiny.cc/lvd2p