I have the DEll wireless card and a Linksys router as well. I got the 128 WEP to work, but it was super slow. When I turned WEP off completely, I could surf with ease. I actually did a speed test at
www.2wire.com and saw a noticible difference between 128bit, 64bit and none. Needless to say, I'm using none. But I didn't want to be totally exposed, so I enabled MAC address filtering on the router. Not sure whats going on. Maybe I have a set-up prob.