It looks like Apple might have removed or postponed network AirPrint functionality from iOS 4.2. When Apple first announced AirPrint they said it would support both specifically compatible printers and printers attached to your Mac or Windows PC as long as they were on the same network as your iPhone or iPad. Now, according to MacStories:
We have been told from a few Mac developers that a few days ago Apple removed all the references to printing via OS X 10.6.5 and PCs both from Readme files and other online documentation posted in the iOS developer center. It seems like all that’s now mentioned in the release notes are the aforementioned HP networked printers, as if the shared printing option never existed.
A reply to a developer from Apple tech support purportedly added:
Support for AirPrint on Windows and Mac has been cancelled. We will be in contact with you if another opportunity arises in the future.
The feature currently works with the iOS 4.2 beta if you have the prerequisite Mac OS X 10.6.5 beta installed. Developers are saying, however, that network AirPrint suffered from instability and incompatibility. It certainly wouldn't be the first time Apple removed a feature from final release that they felt provided a buggy and bad user experience. Then again, enough buggy and bad user experiences have crept into iOS features over the years that even if AirPrint is having some issues, it's impossible to know for certain until the final version ships.
Would you rather Apple get AirPrint right, or get it out right now?