I am doing a migation at the moment of an old 2003 installation to a new fast server with SBS 2008.
I have just finished the update downloading and settings changes asked for in the SBS Best Practices Analyser Tool. I have changed the old server's network settings to a single NIC card configuration from the 2 card setup. (1 to Firewall, 1 to LAN).
Tommorrow I will reinstall SBS 2008 with the aim of migrating in situ.
I will come on line and blog my progress tomorrow.