From Tim Bray's post entitled Atom 1.0 we learn
There are a couple of IETF process things to do, but this draft (HTML version) is essentially Atom 1.0. Now would be a good time for implementors to roll up their sleeves and go to work.
I'll add this to the list of things I need to support in the next version of RSS Bandit. The Longhorn RSS team will also need to update their implementation as well. :)
I couldn't help but notice that Tim Bray has posted an entry entitled RSS 2.0 and Atom 1.0, Compared which is somewhat misleading and inaccurate. I find it disappointing that Tim Bray couldn't simply announce the upcoming release of Atom 1.0 without posting a FUD style anti-RSS post as well.
I'm not going to comment on Tim Bray's comparison post beyond linking to other opinions such as those from Alex Bosworth on Atom Failings and Don Park on Atom Pendantics.