I just wrote about inSSIDer for finding and looking at your WiFi 802.11 signals from a Windows computer. Mac users should try:
KisMACLike inSSIDer, KisMAC is free open source software. In our experience it is the best WiFi stumbling software for the Mac, supporting all standard Mac WiFi drivers and using monitor mode and passive scanning.
KisMAC can be downloaded here.
A great product easy finds my networks
robin
Unfortunately , this will not work with Lion 10.7.2 ( it’s about time they solved the problem)
PLEASE – Pretty Please – make a version for OS X 10.7.3 and above – 10.8 is coming.