So you've got your hands on Vista, installed it and then tried to add the Vista PC to the SBS domain. Doesn't work very well does it? Well the SBS team has been hard at work and there is a fix now! Previously you would have to manually join the Vista PC to the SBS domain, but with this fix you can now use the SBS tools again! All you need to get is the Vista and Outlook 2007 Compatability Update.
There is also information on there about a Vista compatible Firewall client if you are using ISA 2004 with SBS 2003 Premium. By the way all these fixes are for SBS 2003 and SBS 2003 R2.
Update: I hit publish too soon and forgot to include a link to further information. Sorry Mitch! If you want more information than the KB article provides, check out Mitch's blog post on it over at the Montreal IT Pro User Group page.