PCs can use Airports. Wirelessly connected Macs using internal Airports can use Belkin, Linksys, or whatever standards-based 802.11 b/g wireless router out there.

My iMac G5 flatpanel and my son's G4 PowerBook have used the Belkin wireless in my house - though typically use the wired RJ45 because it is there. My G5, and the son's PB and my neighbor's MacBook Core Duo have all successfully connected to her Linksys...

Be aware that certain password strings (WEP?) to get to the wireless router may require a leading "$".