Google, in partnership with Boingo Wireless, Advanced Wireless Group and others is providing free internet access at 47 airports now through January 15, 2010. This is in addition to the free wifi that Google is offering on Virgin America flights.
From their FAQ:
Q. How do I sign up for complimentary WiFi?
No login or email is required, simply select the option for the complimentary WiFi and accept the terms of service.
Find out more, including which airports this service is available from at: http://www.freeholidaywifi.com/