I am trying to get a server to join a domain and in particular an OU during build, I am familiar with this process for 2003, by editing the unattend.txt, but not for 2008 and it's unattend.xml
Hope you can help
I could be mistaken, but you should be able to create the unattend.xml file with the paremeters you need by using Windows System Image Manager. Check out the "Unattended Reference" from the Help menu and look at the "Microsoft-Windows-UnattendedJoin" section under the Components section to read up on how to do it.
Have you looked at using the Microsoft Deployment Toolkit for building and deploying your servers?
We have been using this for about two years now and it has really cut down the number of methods we have had to maintain for building servers and PCs especially around the driver management.