It's only a few weeks since the Google Summer of Code 2011 started and the projects have already resulted in pure awesomeness.
Especially the so-called "Tomato Branch", where Sergey Sharybin is developing camera tracking for Blender has already resulted in some nice and shiny features! He is implementing algorithms of the libmv-project, a tracking library, into Blender. And while we currently do not have 3d camera tracking yet, we already have a pretty decent 2d tracking system. It is really usable and quite stable, and with just a few tiny markers you can achieve impressive results!
Here are 2 tutorials if you are interested to see what's already possible.
And, most impressing, image stabilization of shaky footage in Blender, a method developed by Francois Tarlier.
These are just examples of course, and the workflow can and will be heavily improved.
But it gives a good idea what a powerful tool is being developed here.