I live in Silicon Valley, so I'm in a good position to test those apps that preport to contain thousands of wi-fi hot spots. I've tried four of them with huge databases. My results have been kind of disappointing.
Two of them actually require you have network access in order to look up other wi-fi hotspots. All four of them list the local Carl's Jr. restaurants as having wi-fi when they do not. I am so far underwhelmed with the convenience of these apps and the questionable accuracy of their databases.
One thing that is accurate however is the location information they obtain from my iPod. Surprisingly, they really do know where I am located.
Has anyone found a wi-fi finder app that seems more accurate and will actually help you find wi-fi when you are driving around with an iPod?