You might want to check out AirParrot (http://airparrot.com/). I haven't used it myself, but it seems like it might give you the functionality you are looking for.
Must be.
I find it strange that my 2010 MBP can't use AirPlay when my iPhone 4 can work fine.
Really hope someone comes out with a hack/mod to fool the OS into thinking I have the proper hardware.