Whew, two days... hopefully you haven't bought the gear yet.
The DWL-520+ and the DWL-900AP+ are Texas Instruments based kit, they can do 22Mbs due to some monkeying TI did with the 802.11b spec, but they're kinda an evolutionary cul-de-sac.
Also, TI refuses to support them under Linux, so even though there is a driver for the DWL-520+
acx100.sourceforge.net
It sucks, since it was engineered with no information about the card.
There's better 802.11g kit out there that'll get better speeds, range, and is around the same price and has "relatively" simple linux support to get running. Atheros and GTPrism or Prism Duet gear listed on this site:
http://www.linux-wlan.org/docs/wlan_adapters.html
Cheers,
Finegan