Are AT&T phones in California on Tri band GSM 900/1800/1900 Mhz?
From what I can find, AT&T is operating on 850 Mhz in California, at least in the Bay Area. Tri-band phones are operational, but will use 1900 Mhz so coverage is limited to where those towers are. The engadget link below gives some background, while the forum provides more discussion on the subject.
