Sebastopol, California does NOT have 3G. Earlier today, I couldn't get 3G in Petaluma or Rohnert Park either, just Edge. So far, the only place that I know of around here that has 3G is Santa Rosa. I called AT&T about being charged for a network I don't get and they said, "sorry, the iPhone 3G only has one plan." When I asked her about when 3G would be available in Sebastopol, Rohnert Park and Petaluma she said, "Don't expect it anytime soon."
UPDATE: I've just noticed here at home in Sebastopol that when I turn on Airplane Mode, then turn it off, the iPhone shows "Searching..." and then, 3G! However, it doesn't stay 3G for more than a few minutes and also there is only one bar for voice showing. It then changes to E and a couple of voice bars. I checked the speed when showing 3G on iNetwork and it came back 241 kbps, in other words, Edge.
UPDATE #2: I was just at the Santa Rosa Plaza Mall AT&T store inquiring more about the 3G speed test. While in the store I got 409.8 kbps (they've got a mini-tower in the back!). According to the guy I was talking to, I very well could be getting 3G in Sebastopol from a rogue tower because 241 kbps would be towards the top end of Edge speed and not likely with the poor reception I get there. So I turned off the 3G (to go back to Edge) and ran the speed test from the same location in the AT&T store and got 190.4 kbps, so perhaps he's right! 🙂
Speeds Recap:
1258.1 kbps (WiFi in the Apple Store)
409.8 kbps (3G, AT&T store)
241 kbps (at home in Sebastopol, supposedly on 3G)
190.4 kbps (Edge, AT&T store)