I've been cruzin the net today looking to turn my old IBM 41 Tower into a linux Wireless Box. After looking for a new card that is compatible for Windows or Linux I came up with this

TP-LINK 54 Mbps Wireless G PCI Adapter w/SMA TL-WN551G - eBay (item 350115333047 end time Feb-22-09 12:49:00 PST)

I'm posting this here because it works in Windows Also. I would also like to see if anybody can find a better deal on a Linu/Windows card.