The official blog for Windows Server Essentials and Small Business Server support and product group communications.
[Today's post comes to us from Chris Puckett]
There is a bit of a delay in getting the update released for KB 926505 that was originally scheduled for around the end of January. We will update the community with a new date shortly. In the meantime, you may follow the steps listed in KB 926505 to manually join Vista clients to an SBS 2003 domain.
926505 You cannot use the Windows SBS 2003 client deployment tools to join a Windows Vista-based computer to a Windows SBS network
The Official SBS Blog : Update for the Windows SBS client deployment tools to support Windows Vista delayed: