How to Enable and fix AirPrint on any iOS 4.2 device (iPhone, iPad or iPod Touch)
With the new iOS 4.2 (and 4.2.1) firmware for all mobile Apple devices, printing from your iPhone, iPad or iPod Touch has become easy… well, maybe not. Despite the new AirPrint software in iOS 4.2, it can still be difficult to print papers and photos from your mobile device since Apple removed AirPrint from the Mac OS X 10.6.5 software update, due to some kind of legal dispute.
To help you master AirPrint, Lifehacker made this video on how exactly to enable it, and more importantly, how to print that image (or whatever) wirelessly, to any wireless printer. You'll need to download the relevant files and copy them to three specific locations:
See more details @ lifehacker.com.