Do some research over the Internet. It depends on what you require. In my setup I have a wireless broadband router for sharing Internet connection. I just put a USB wireless adapter card in my XP desktop (or any notebook with Xp or Win98se), it will talk to the router. Because other PC/notebook can also talk to the router via wired or wireless connection, I have all PCs communicated with each other this way. Techically the setup I have is working in a so-called infrastructure mode.
If you do not have a router or want to have one, you could still make your machines to comunicate by buying 2 wireless adapters: one installed in your notebook (xp) and one in your host with Win98. In that case your wireless setup must be setup in ad-hoc mode. I haven't done this before but I think it works. good luck
