Dumb(?) networking question

I'm wanting to set up a wireless network here at home and am not quite sure
where to start. I have a desktop running XP Pro, a laptop running Vista
Ultimate, and a Linksys WRT300N wireless router connected to my cable modem.
I also have a Netgear wireless media receiver connected to my stereo system
and a D-Link USB wireless adapter. Since the modem and router are located
adjacent to my desktop, the desktop is currently hardwired to the router.

I have no problems at all connecting to the Internet with my desktop, laptop
or IPaq, but here is my question: what do I need to do to enable connecting
my laptop and/or the Netgear wireless media receiver to my desktop? I want
to connect my laptop to the desktop for testing purposes during development
of a Web site running under IIS on the desktop. I'd also like to be able to
play all my MP3 songs on the desktop served up by Netgear's Media Server.
Should I plug the USB wireless adapter into my desktop for communicating with
the wireless router and buy another wireless device, connect it to the
network port on my desktop, and communicate with the desktop via that device?
Or is there another way of accomplishing what I'm wanting with the equipment
I already have?

Thanks!

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