Newbie searching Google for 1-2 weeks and now I finally have my wireless internet working!
I have debian 5.0 KDE installed on my old Dell Latitude C600 (which by the way works like a charm), but I couldn't figure out why the wireless usb wasn't working (hardware was recognised, but couldn't be activated).
Solution was pretty simple:
1) Don't rebuild the kernel (as adviced in many posts) to get the latest zd1211rw driver, Lenny has it by default.
2) Download zd1211 firmware at:
3) unzip and untar
4) mkdir zd1211 at /lib/firmware/
5) copy ALL the extracted files (the readme says zd1211_*, but that's not enough) to lib/firmware/zd1211/
6) And presto
Hope that this post can save people some time!