Although the driver ships with lenny, you need to download the firmware, the firmware does not ship with lenny as the license, allthough free to use, is not free in the Debian sense, you can not reverse engineer it, and that is not what debian considers free….
So what to do, when i visit the website for the file ( http://www.ralinktech.com.tw/data/RT61_Firmware_V1.2.zip ), the website returns a 404 not found !
The requested URL /data/RT61_Firmware_V1.2.zip was not found on this server.
So what you can do is the following
1- Edit /etc/apt/sources.list
Add a line such asthis one (Change the mirror if you like by changing US)
deb http://ftp.us.debian.org/debian/ lenny main non-free
Open synaptic t (or use aptitude or apt-get)
Update the package list (In my case apt-get update) then Install
firmware-ralink
You should be good to go, clicking on the network icon in the top right corner of the screen should show you wireless networks, and once connected to them, the command
ifconfig wlan0
should show you the expected information.
Happy wireless networking