So is the is Powerbook G4 802.11g or b? it is the 1.25GHz model. Also, one thing I don't understand regarding the airport extreme or any airport for that matter: isn't the maximum speed going to be completely determined by how much the cable provider, Comcast, pumps out? If this is the case, how do I determine what my transfers and speeds are looking like specifically for Comcast? And, how would an airport extreme improve upon this or any other performance aspect in this regard? Thanks very much.