I have been searching the web for a clean solution on how to migrate our 2010 tfs collections to our new tfs 2012 server, but no luck. May someone please assist with the steps or a good blog I could look at to achieve this process. The reason we want to do a MIGRATION and not an upgrade is because we got new hardware and would first like to trial TFS 2012 before we upgrade our live environment. Therefore we would like to import all our collection including the work items and build process templates.
You can move a collection at a time using the detach option in 2010 and attach it back to 2012 using the attach option there.
See http://msdn.microsoft.com/en-us/library/dd936138(v=vs.100).aspx