Speaking of open wifi points, I wrote a program to import NetStumbler summaries into Google Earth. It separates them into open and secure, so you can just view one type at a time, or both.
http://mboffin.com/earthstumbler
I use it to keep track of points I've found before so I know if there are upcoming open access points while I'm driving. I'm currently working on a version that is basically a bridge between NetStumbler and my
Earth Bridge program, so you would get a live stream of access point placemarks flowing out behind you as you drive.