The best free software I know (and use) is CamStudio
However it is quite difficult to configure properly. You need to use their own video codec (provided for free on the site) but it's a little tricky to make everything work. Fraps
is very good and specialized to make game catpures. It works with Visionaire, but it's not free.
The very best video recorder that I know is Camtasia
But it's not free at all... So CamStudio (first link above) is the best alternative.
I have also found recently the free Srecorder
that I have never tried:http://srecorder.com/
On their site it looks promising. If someone tries it, I'd love to know their opinion!