It is a Broadcom running at 200MHz I think. Back then the Airport was horribly expensive, and I would have no way of managing it since there was no Apple-branded device in the house. Really the WRT54GL provided the best bang for the buck as a requirement for proper high-speed connection was MLPPP, which Airport doesn't support.
I am not sure when the Windows version of AirPort Utility came out. Then again, I really don't have a reason to know