SFO would join Boston, which is finalizing its free decision; Seattle-Tacoma, which switched over this month; and potentially, Atlanta. Denver started offering free Internet access at the end of 2007.
SFO has competition in its area with two smaller airports: Oakland in the east bay and San Jose in the south bay; both of those airports switched to free Internet service in 2008.
Don't cry for the service providers who operate networks in these airports; that's primarily Boingo Wireless, which under the Concourse brand has the lion's share of airport operations; AT&T and T-Mobile operate most of the rest. Airports aren't inclined to run their own Wi-Fi networks, and thus providers may shift from the hassle and cost of collecting fees and splitting revenue to providing a fee for service, which is much more reliable income over the long haul.
U2’s Christopher Lawrence bootleg free to download hereTalking about Airport Wi-Fi on Public Radio