Control-click brings the magic.
You've made it through the line, finally foisting the iPhone 3G upwards like the captain of a hockey team with the Stanley Cup. If you're upgrading from an original iPhone, here's how to transfer your old settings to the new device.
Plug in the new iPhone, and Control-click its name. This phone is just called "Apple's iPhone" since we didn't bother coming up with a name while in the store. Choose "Restore from backup," and pick the name of your prior phone from the next screen.
Wait several minutes while iTunes transfers network settings, mail details, and other information. The new iPhone will then take the name of the old phone; click the name once, and press Return to rename it with a snazzy new moniker. Finally, sync everything to the new phone.
When finished, your new iPhone will have the same contacts, calendar, and applications as the original. And unrelated to this brain transfer, your old iPhone should behave like an iPod touch. (Ours, upgraded to version 2.0, did as soon as their SIMs were deactivated.)