Yep, the REST-based API is part of the OpenSocial 0.8 specification.
Good progress is being made in Shindig, the OpenSocial implementation
that orkut uses, but there is no formal completion date as of this
time. Stay tuned to the blog, which will be updated when we have a
better time frame.
http://orkutdeveloper.blogspot.com/
Here's a link to the Shindig project if you're interested in
contributing:
http://incubator.apache.org/shindig/
- Jason