There is usually one here ...
http://linux-wless.passys.nl/index.php ..., but it's been down for the last week or so.
I recommend a card with a Realtek chipset ... the rt2500 is particularly well supported.
Stay away from ndiswrapper and madwifi, too ... madwifi is quite Linux friendly, but it's not free, and, as such will never be simply built into standard kernels.