It seems that AirPlay is more or less Mac-ready. No word on whether Apple will ever officially support this, but creating a 3rd party app that streams AirPlay content from iOS to the Mac appears to be easy enough.
"While Apple's AirPlay feature introduced in iOS 4.2 allows users to stream certain video content from their iOS devices to the new Apple TV, users have been wondering if the service will ever be extended to allow content to be streamed to their Macs in a similar fashion."
Read the full post at: http://www.macrumors.com/2010/12/14/airplay-reverse-engineered-to-send-video-from-ios-devices-to-macs/