WPA on an RA2500 is supported out of the box on Ubuntu, using Gnome Network Manager. You used to have to do a smidge of terminal stuff pre-Gutsy, but now it just works
I have a Belkin F5D7010 (same card, different name) on my oldest Dell.
It was one of the few cards that had any level of support some years ago.
I agree - it's a good buy. Even more so at that price.