The G1 or Android developer phone both require a gmail account to work properly. The phonebook on the phone is automatically synchronized with the associated GMail contacts. Once anybody acquires a phone, the first thing that is needed to be done is to put your phonebook to google contacts. Here is what I did and it worked.
Most of the phones allow the phonebook to be synchronized to Outlook, that should be the first step that you take. Once you are in the outlook or outlook express, export the phonebook to a CSV format.
Go to GMail contacts and import this CSV file. After successful import, you can cleanup the phone book on your computer. Now as soon as you powerup the phone and it connects to google, the phonebook will be synchronized to your phone. From there on it is a two way automatic sync so one does not need to worry.
Many times when you try to import the CSV file to GMail, you will get a message saying that "an unknown error has occurred". Following work around can be tried and it worked for me.
On the top right menu in Gmail, switch to Older Version of gmail and then perform contact import. After that it works and gives you messages on how many contacts were imported and how many could not be imported.