Developers have found an on/off switch to enable 3G in the latest iPhone 2.0 Beta. By default, the preference is hidden, but Chronic Productions claims to have activated it.
Well, when you have nothing to do all day, this is what happens. Note that this is not fake, it is in the beta 5 .ipsw, but will normally not show up on an EDGE iPhone. Turning 3G on will just crash the phone if you use an EDGE phone. If you do not believe me, then decrypt the beta5 rootfs dmg, and see for yourself in /Applications/Preferences.app/Network.plist