A few years ago, Google teamed up with a number of airports in the U.S. to provide travelers with free WiFi during the holidays. This year, it's Skype's turn to make a similar offer. From December 21st thru December 27th, Skype (and, by extension, Microsoft), will offer free access to third-party WiFi hotspots through its Skype WiFi program in over 50 airports all across the U.S. Given that you have to use either Skype for Windows or Mac, or the Skype WiFi app for iOS, this is obviously also a promotion for this service, which the company introduced a few months ago.
This promotion includes virtually all of the major U.S. airports (and quite a few smaller ones) that don't currently offer free WiFi.
Skype's offer is obviously less generous than Google's past promotions (which was valid until January 15th), but if you are traveling during the holidays, now is probably a good time to install Skype's WiFi app on your laptop or iOS device.
Outside of this promotion, Skype WiFi can be a good option if you find yourself in need for a quick Internet fix, but don't need a full hour to just download your email, for example. Prices start at $0.06 per minute, though the app will provide you with the exact pricing depending on whose WiFi network you are using and where you are.