When iOS 4.2 was released, users were slightly disappointed at the gimped AirPlay feature. It can only be used in certain 1st party apps, and is severely limited in Safari. An excellent workaround created by Erica Sadun and Steven Troughton-Smith spawned the Cydia app AirVideoEnabler, which allows AirPlay to be used in all 3rd party apps, they way it should be.
According to Jobs himself, AirPlay should get these features natively sometime in 2011, so un-jailbroken devices will be able to use AirPlay in all of its unrestricted glory. There are rumors that iOS 4.3 will be dropping sometime in December, but it is possible that this update will be saved for early 2011, and include this crucial AirPlay update.