From http://www.wikidata.org/wiki/Wikidata:Project_chat#Deployment_schedule
:
If everything goes well, we will deploy a new version of the Wikibase extension today to Wikidata, probably around 7-9pm UTC (i.e. in the next few hours). Things might go wrong, deployment might stall, or we might need to retract. The API will change quite a bit (you can see the new API on the test repository http://wikidata-test-repo.wikimedia.de/) and also there are a few fixes and new features (List of pages without a label, yay!) that will be rolled out. The API will very likely break the bots, but should be quite stable then (no promises, though). No Phase 2 features will be rolled out yet (we removed them from deployment code). We would love to get feedback and bug reports. A lot of code has changed in the backend to enable the data propagation to the clients.
If all goes well, we will also deploy a public client to use the data from Wikidata. If the repo, the client, and the synchronisation work well for a few days, we will aim at deployment to the Hungarian Wikipedia. If anything goes wrong, we won't deploy to the Wikipedias in 2012, but in early 2013 (as we want to make sure that we are available for fixing Wikipedia in case something goes wrong).
So, this is the current plan. Things might change, but here is to keep you posted.
Cheers,
Denny