No idea yet. The Nexus One (a google phone) hasn't received Gingerbread yet. So once the N1 gets it, then I expect others to slowly start doing the same.
The only phone currently that has it is the Nexus S. So, don't get over-anxious. It'll probably be a few months before it comes out.
As far as rooting, it's fairly simple. There should be guides around here somewhere...