Active Directory Migration from Windows server 2003 SBS to Windows 2008

Our company has an existing windows 2003 small business. Active Directory is running and we have a domain and also sharepoint. We are now planning to migrate to Windows Server 2008 Standard Edition.

The existing domain is installed in an older server and the Windows Server 2008 will be installed in a new blade server and will act as the new domain controller.

I wish to maintain the same domain name and all the objects under it. Is there a standard procedure How to migrate all the user accounts or the whole domain itself?