Camstudio is pretty good. I used a commercial version of it to create the sample videos here: http://www.screen-capture-video.com (I don't own the site, but I was hired for the application's interface overhaul and created the sample videos, including the audio.)

You might also find Fraps useful (and free). And if you need intro/outro music, I have some freebies on my site. :)

--Donnie

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Posertrax
Music & Sound FX
www.posertrax.com