+1 for the netgear MA401, got one here

works fine with WEP, last i heard that for the drivers to support WPA/2, it was a cost option. but still an option. if they've been made freely available, i may have a reason leave the old 802.11b option ticking over on the router since my last Ninty DS has need passed on the niece's / nephews, and have since switched off WEP...
if you want a wifi driver and IP stack set, then amigakit do their "easynet" software bundle, which works really well

and isn't time limited like others.