I'm currently using a Raspberry Pi running Shairport connected to a HiFi to act as Airplay speakers.
Using Airfoil on my Windows 7 laptop I can send all audio to these speakers with a 2sec delay- good for music but useless for video.
My friends iDevices all work perfectly with this, playback of video on the device automatically syncs with the audio. This works for all media; Youtube, music, webpages, BBC iPlayer etc.
Is there a way of getting this level of seamless audio streaming with Android devices, either working through Airplay or an alternative method (pulseaudio possibly)?