Here's a quick demo of the tracking workflow in Blender, as it was this morning. But it already has gotten better by now. :D Hard to keep up with development! This is becoming a serious alternative to other (commercial) trackers. When GSOC is over, we've got a mature tracker right there.
Music: Doctor Strangelove
Btw, if you want to know more about compositing in Blender, check out my 3d compositing tutorial on cmiVFX.com cmivfx.com/tutorials/view/255/Blender+3D+Compositing
It covers all you need to know to integrate 3d elements into real life footage (does not cover tracking).