Back in January, we reported that Apple had begun approving third-party apps that support AirPlay, Apple's new wireless audio streaming protocol for listening to iPhone or iPad music over a speaker system hooked up to a compatible Apple networked device, such as an Apple TV or an Airport Express.
But few applications so far have released updates to take advantage of that capability. However, you can easily trick your iDevice to stream audio from an unsupported application to your stereo.
All you have to do is go into your iPod app, start a song and choose your AirPlay speakers. Then return to your home screen and boot up the app that has the audio you want to hear. Your iDevice should automatically switch audio source from iPod to the app, because most apps, when booted, retain the current state for audio output, which in this case is AirPlay.
Bingo. AirPlay on apps like Hulu, or Pandora! Note that this only supports audio, not video. Apple has also announced some updates to AirPlay in iOS 4.3, coming next week.