There is a very basic program that does some of the same things that NetStumbler does called APSniff. You can download it at http://www.bretmounet.com/ApSniff/ . Read the whole directions through before installing. It should work just fine for anyone using a WLAN card with a Prism 2 chipset like your Linksys card.

Konrad Roeder
Consulting Systems Engineer
http://www.springswireless.com