having just passed through London Heathrow airport, Minneapolis and Phoenix, I have some experience here.

PHX has free wifi, I was able to connect through it and ring my wife (in england) using the n800's voip client via the Sipgate service - much cheaper than mobile phone roaming!

MSP has boingo, which costs money. I did try the NorthWestAirline's executive lounge's wifi (from outside) but neither the tablet nor my (linux) laptop worked - the laptop would only associate for a short while and drop. No idea why. There were other wifi services around the airport, some ad-hoc, none gave me useful service - some didn't give me a useful IP address and avahi kicked in and picked a random one.


LHR has BT Openzone, I have some connection credit via my employer, it worked pretty well.

I was also able to make use of the free wifi at Starbucks in Arizona - picked up a free card at the cashier, paid $5 to load the card, used that to buy coffee, registered the card in the outlet using my n800, signed up to the free wifi there and then, signed in and it worked straight away!

HTH
Paul