Multiple Exchanges and domains

Id like to take my time and migrate users over to the new server/domain name.

Are you talking about the Active Directory internal FQDN? or are you talking strictly about the SMTP domain name has changed?

If this is just the SMTP domain name all you need to do on your new version of Exchange (2010?) is create a new Email Address Policy and assign it to a new Accepted Domain. You can have multiple Accepted domains and you can have your users use the new SMTP domain as primary and their old SMTP domain as a secondary alias (so they can continue to receive email if it was sent to the new account).

If you are talking about a New Active Directory FQDN then this is a lot more work involved.

I just relaized that Exchange 2003 does support Domain Name changes

You can also rename the domain if you are 2003 FFL and DFL (domain/forest functional level)
http://www.msexchange.org/articles-tutorials/exchange-server-2003/migration-deployment/Domain-Rename.html

Will.

Thanks... I was talking about external domains... Right now my mail is @blah.com and I have another I would like to move everyone over to that is blahinc.com ... However the current server is a bit old and would like to get a newer one so I figure why not kill 2 birds at a time with a new server and new domain name.... Then move people over to the new blahinc.com as time permits.

This transition would be pretty straightforward then. As stated all you need to do is perform the correct Schema updates to Active Direcotry, install Exchange 2010 on new hardware.
- Create your accepted domains
- Move mailboxes over
- Pulbic folders
- Email Address Policies
etc...

Will.

Thanks any particular guides? I just want to make sure I dont screw anything up on my current enviornment while I am adding the new server.