I have this old SBS2003 server. Over time, I've replaced Exchange, Sharepoint and all the other SBS services with other services. This SBS is no longer being used as SBS. This server is about seven years old.
About 2 years ago a w2k8 server was added to the network to do the fileserving, including all users' "Documents" folders.
Thankfully this network is small, 10 workstations, plus 3 VPN clients.
Rather than wait for the older SBS server to fail, I'd like to turn it off and let the w2k8 server be the PDC.
What will I need to do in Active Directory to safely remove the old SBS2003 server and promote the w2k8 server in its place?
There is no more Primary/Backup domain controller functionality in Active Directory. Everything is handled by roles.
In a nutshell, you want to: promote the 2008 server to become a domain controller, transfer all roles to it, then remove the 2003 SBS box.
Here's a Technet Wiki article to get you started: Migrating AD DCs from 2003 to 2008 (links to the full article at the end)
We had a lot of problems with the FISMO rolls when doing this. Microsoft built in a time bomb of 7 days I believe, once the rolls are transferred. If the SBS server is still on the network after the rolls have been transferred it may try to take them back, so be aware of this if you want to leave the SBS server on the network for a while after the transfer. It can really caused a mess of things after you think all is well.
Here's the FSMO role seizure article just in case you may need it.
http://support.microsoft.com/kb/324801