Here is a link you should look at:
Read it all of the way through before you start because there are some addendums pertaining to getting fwcutter and downloading the appropriate drivers. Also make sure you have wireless-tools package installed, and if you are using wpa or wpa2 for security, you will need to install the wpa_supplicant package as well.
Finally, network-manager didn't work for me, so once I followed the link I posted above, I modified my /etc/network/interfaces with the appropriate info, and then ifup eth2 (unusual, but the wireless adapter on my Etch laptop).
Wifi Radar is a great program once you get your wireless up and running. I use it when I have my laptop away from home.
Hope this helps.