So I decided to jailbreak my iPhone 3G solely for this app, PdaNet. It's a very simple but amazingly useful tool, it let's you use your AT&T 3G connection on your laptop. So basically you connect you iPhone and laptop together via WiFi and then over your 3G connection your laptop can browse the internet.
My point is that anywhere you have cell coverage you can get online with you laptop, for "free". So you'll never have to worry about finding a WiFi spot, just bring your iPhone along and you're good to go.
Over at: www.iSmashPhone.com they have several very good tutorials on how to jailbreak your phone and how to get PdaNet up and running. The one that I used to get PdaNet up and running is this one here.