Very few places have free access that I know of. IDE had it in IAD after the launch of independence. That's the only place that I ever found company sponsored wireless.

There are some airports out there that have free connections. CAE comes to mind off the top of my head.

Turthfully though- I never took the time to pull out the laptop when I was in the crewroom. There's usually not enough time to deal with the hassle.