There is nothing built-in but it would be straightforward to update your model data over web sockets. The magic of Ember bindings and observers will take care of the rest.
Saying it would be straight-forward is a little bit of an exaggeration.
While, true, Ember will happily update any model pushed to it the difficult bit i.e. pushing the right data to the right model (on the right client) and only the right model to only the right client is an exercise left to the reader.
The cleverness of Meteor is not in the push, it's in the logic just before the push.
That's true, Ember doesn't have any data synchronisation mechanism over websockets like Meteor does. It is easy to update your data model from incoming messages but, as sambeau points out, pushing these data updates may not be a trivial matter.
I started down this path a month or two ago and you're right - it's actually quite a big job. I've been working on a real time system for rails / ember that moves all data over a websocket and allows subscribing to updates, however it has been very hard to get working with ember-data. I've currently have it running with my own (terrible) data layer but I would really like to get it running with ember-data again before I get it up on github.
While, true, Ember will happily update any model pushed to it the difficult bit i.e. pushing the right data to the right model (on the right client) and only the right model to only the right client is an exercise left to the reader.
The cleverness of Meteor is not in the push, it's in the logic just before the push.