This card is a mess (the Linksys WFC12). I've tried the drivers on the original CD (Setup Wizard version 1.05 according to the CD label), the newest, publicly posted drivers on the Linksys site (
ftp://ftp.linksys.com/pub/network/WCF12_011904.exe), the beta drivers (which I got by calling into Linksys three seperate times until I finally go to a 'Sr. Tech Support Engineer' who emailed them to me(unfortunately I can't post them here, but it hardly matters because they don't seem to work either), and finally the Senao drivers mentioned in this thread. I had luck with, I THINK the Senao drivers because I did eventually get a wireless connection both at work (with WEP enabled) and at home (a wide open connection [naughty me, I have to secure that!]). Unfortunately, the card sucks power from the battery like there's no tomorrow. It certainly won't last a weekend's worth of moderate wireless use on a single battery charge. Consequently, my iPAQ lost it's configuration! Argh... so here I am trying to get the thing to recognize the card again and I'm going through the same problems I did last time... IMHO the Linksys WFC12 is not ready for use with Windows Mobile 2003 (aka Windows CE 4.0).
I have heard that the latest posted drivers (see link above) do in fact work, but you a) install them, B) soft-reset the PocketPC, c) insert the card, d) remove the card, e) re-instert the card and it should work. It didn't for me, but according to a different thread on another board, it does work.