Here are some useful links:
Screencasting software:
Windows
FRAPS
http://www.fraps.com/ (not free)
Camstudio (do not confuse with Camtasia Studio)
Open Broadcaster Software (free, works on Windows, Mac, Linux)
https://obsproject.com/
Mac
Screenflow (not free but great)
http://www.telestream.net/screen-flow/overview.htm
procaster
Windows
FRAPS
http://www.fraps.com/ (not free)
Camstudio (do not confuse with Camtasia Studio)
Procaster
http://www.livestream.com/procasterOpen Broadcaster Software (free, works on Windows, Mac, Linux)
https://obsproject.com/
Mac
Screenflow (not free but great)
http://www.telestream.net/screen-flow/overview.htm
procaster
Linux
RecordMyDesktop:
http://recordmydesktop.sourceforge.net/about.php
GLC
http://www.dedoimedo.com/computers/glc.html
Wink(freeware):
http://www.debugmode.com/wink/
xvidcap:
http://xvidcap.sourceforge.net/
Cinelerra:
http://cinelerra.org/about.php
Kino:
www.kinodv.org/
Other:
http://www.screentoaster.com/ (web-based)
http://www.screentoaster.com/ (web-based)