I needed to duplicate my primary DHCP scopes to a secondary DHCP server so I could perform maintenance on my domain controller. Both of my servers are 2003 R2. I came across the following procedure on the Microsoft support site for moving from Server 2003 to 2008 and decided to give it a try.
The procedure worked and was quick and easy to implement. I received an error message at the end however upon stopping and restarting the DHCP service I could see all my scopes and reservations on the secondary DHCP server.