Migrating to New Domain

Hello,

I am hoping someone can offer me some advice/guidelines to follow with
migrating from one domain with 2003 DCs to another domain with 2008 DCs. The
person who started this has left the company and I've been asked to look into
getting it completed and I could do with some helpful assistance.

The setup for the current domain is as follows:
2 DC's, both Server 2003, both GC servers with 1 DC holding all the FSMO
roles.
Currently in W2K Native Mode

The setup for the new domain as it had been left is as follows:
2 DC's, both Server 2008, neither are GC servers with 1 DC holding the
following FSMO roles: fsmoPDc, fsmoINFRA, fsmaRID. The others aren't assigned.
Currently in W2K3 Domain Mode

There is currently a Windows 2000 trust between the 2 domains.

Correct me if I'm wrong but, as I understand it, I need to put a Server 2008
DC into the current domain in order to use ADMT 3.1 to carry out the
migration. I have the lengthy ADMT 3.1 document to go through but, as I asked
at the beginning, could someone offer me any advice/guidelines that I need to
do to ensure the migration is successful?

Many Thanks
Mark