I live in an area dense with Wi-Fi coverage. Eight SSIDs show from my menu bar dropdown, but I know there are more. Where can I view a full list of networks in my area? (I'm on a 2011 MacBook Air running 10.8, but it'd be nice to know in general.)
Get a copy of iStumbler. That should do the trick
Nice one is the NetSpot app. Simple application to locate and visualize wi-fi spots.