Recently I've been having a little play with preparing stand-alone instances of SQL Server 2008, otherwise referred to as sysprep. I considered writing a guide with screenshots but it's already been done. So in the spirit of not wanting to reinvent the wheel, here we go: http://blogs.msdn.com/b/petersad/archive/2009/12/17/sql-server-2008-r2-sysprep-step-by-step.aspx
