U Said that you are going with SBS 2008.
After installation/creation of the SBS enviroement. Setup new domain accounts on the Server.
Make sure you have your DHCP and DNS working.
Once you have confirmed that DHCP and DNS is from the SBS Server, on the wktns..
just run http://connect from a browser.
Follow the prompts and the wizard will move all data/settings to the respective domain accounts.
Repeat this for all wkstns.
Pretty simple...
Hope this helps..
..BigSquish.