AIR, Bootcamp won't even install on a PowerPC Mac (G3/G4/G5). Don't bother trying VMs using Fusion or Parrallels - Bootcamp is the way to go. Also, Bootcamp is free, shipping with 10.5 Leopard and on, or can be downloaded from Apple for later versions of 10.4 Tiger.
AH runs fine on my 13" MBPro under Bootcamp. Not brilliant, but good enough to play.