Some bootable linux distros will have the tools that you need. Try knoppix-std.org, which contains the following tools on live distro CD:
wireless tools
/usr/bin/wireless/
* airsnarf : rogue AP setup utility
* airsnort : sniff, find, crack 802.11b
* airtraf : 802.11b network performance analyzer
* gpsdrive : use GPS and maps
* kismet 3.0.1 : for 802.11 what else do you need?
* kismet-log-viewer : manage your kismet logs
* macchanger : change your MAC address
* wellenreiter : 802.11b discovery and auditing
* patched orinoco drivers : automatic (no scripts necessary)
Also, just read a /. article and there was mention, I believe, of Kismet finding twice as many APs as Netstumbler.