The Apple TV has no full operation system on it. So to start you would have to hack it and install Leopard or Tiger or something on it. Then Itunes and Frontrow or the ATV application. I am not convinced though that Beoport would control the ATV application.
http://www.macgeekblog.com/blog/archive/2008/03/25/atv4mac-1-2-available-2.html
I am assuming though that ATV works just like frontrow which I am not sure off. I think a safer bet is to run it through the STB of you Beovision if you have one.
Cheers
JK
BS9000, BS2300, BC2, BL2500, BL3, Bl2, BS1, BV8, BC4, A8