T-Mobile has its fingers on Delta, United, US Airways, and American, but Continental goes it alone and free: Continental will make free service available in its club lounge, Presidents Club, in 29 airports but not in Chicago. They may be bowing to O'Hare in terms of the upcoming Concourse Communications rollout in that airport, even though the FCC said that landlords can't control legal use of spectrum by tenants.
Continental is the first airline of any scale to offer free Wi-Fi. JetBlue and AirTrans offer free Wi-Fi but only in a few of their national terminals, not everywhere they fly.
I suspect that Continental might not offer WiFi at their Chicago Presidents Club because it is jointly operated with Northwest Airlines whose World Clubs do not always have free WiFi. In my book, this is just another example of Continental doing their best to provide the best value product to their customers.
Continental's massive Houston hub "leaks" its Wi-Fi signal down one floor to the main walkway below and everyone including at ton of CO flight crew use the free Wi-Fi to gain net access. It may not be as comfortable as being in the President's Club, but it's easy and free.