Steven J. Vaughan-Nichols thinks Xandros might be the answer for SMB users who want to ditch Windows in favor of Linux.

One reason I do that is that Xandros comes ready to work with both NT PDC (Primary Domain Controller) domains and W2K and Server 2003 AD (Active Directory) networks. This isn't just hype. I currently run Xandros on my main laptop and a secondary workstation on my hybrid Windows network, and I have no trouble working with NT, W2K and Server 2003 drive and printer resources. You'll have endlessly more trouble trying to get XP Home working with either PDC or AD-style networks.

I guess I need to take Xandros for a spin. I'm still a big fan of debian on servers.