How can I view all Wi-Fi network names (SSIDs) in my area?
Solution 1:
There is a program you can run in terminal.
/System/Library/PrivateFrameworks/Apple80211.framework/Versions/Current/Resources/airport -s
Update for 2021: This command still works (as written) in OS 11 Big Sur.
Solution 2:
Get a copy of iStumbler. That should do the trick