I'm new to the Mac and am trying to set up a wireless broadband connection using Telewest. What exactly do i need and how much will it cost? Or even can someone put in the direction of some reading material that makes it sound easy. I've read the manuals and it mentions Airports etc but i dont want to go out and spend money when im unsure of whether it'll work. Can i get USB alternatives???

I have a 2.0 Ghz G5 Powermac.

Please help!!