I've never done this before, so was hoping to get some advice. We have an existing AD server on say OLD.edu DNS domain space and need to retire that old 2003 server. We are building a new 2008 windows server with a new DNS domain space called NEW.edu to replace the old one. And of course all of our existing servers (web, storage, data, etc.) use/point to the main AD/DNS/DHCP for authentication and such. Can anyone give some or complete advice/checklist/planning (things to do 1st, 2nd, 3rd, etc.) to accomplish this w/o causing too much downtime (if any at all) during this switch-over?