Free software for annotations (circles, arrows, etc.) in screen capture videos I have recorded some technical tutorial videos through screen capture. At certain points in these videos, I want to highlight buttons, text, etc. by circling them or putting arrows. An example effect can be seen here: 
                
            

I know there are paid software out there -- Adobe Premiere Pro, Camtasia Studio, and the like. Is there any freeware that can help me achieve the same?

Related question: Video tutorials: how to add labels, comments, arrows etc
There's CamStudio (GNU General Public License): http://camstudio.org/
It has screen and video annotations tools.