SME does PDC right out of the box ... a simple setting in the server manager allows domain services with or without roaming profiles. Don't forget that with or without roaming profiles, 2K and XP machines will need settings & documents copied to the new domain user profile on each workstation after the domain is changed. Personally, I wouldn't jump from domain to domain directly; I'd change each workstation to be a member of a workgroup first, then join the new domain.