I have gone through amazing iphone accessories that you guys are doing to add functionality into current iphone, but is it possible that these circuits are converted into an end user product so that these can be used as well. I couldn't find a single website (within my last half hour research) that is selling these kinds of accessories.

I have gone through "iPhone infrared receiver - using iPhone 2.0 SDK, no jailbreak required!", "iPhone RS232 at 1200 baud - no Jailbreak required, using 2.0 SDK" and I really like all this technical information.

I have also read about the book that is released in April 2009. I will try to get this as well.

Best of luck !