Hey'll
I'm running Windows Server 2003 SBS & I'v recently had to restart the whole configuration since it was an enherited setup, our problem is that once the server is promoted to a DC status it takes about 30 - 60min just to load the operating system, prepering network connections e.g

The same goes for shutdown process as well, but once I demote the server everything smoothens out, what could be causing this delay ? Its on a xseries 206 IBM machine.

SBS is limited to a single forest, single domain model. Is this the case? Are there any other DC's in the domain? Is it connected to the Internet and are you using a unique domain name from your company domain name (ie. Company.com for external and company.net for internal)? Is DNS installed on the SBS server and all other DC's?

Check your Event Logs (Application, DNS and System). Are there any errors?