Demoting domain Controller with exchange server 2003 running on it

HI
My domain controller is a windows 2003 server and it has exchange server 2003 running on it. It is working fine but it is actually a desktop pc very very slow.

I have just bought a new Dl380 g5 server and i want to remove this domain controller and use the dl380 as my new domain controller with exchange 2003 running on it

How can i achieve this transition smoothly please advice

thanks

jimmi