https://wiki.ubuntuusers.de/Skype/


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( http://community.skype.com/t5/Linux/video-is-not-working-on-Ubuntu-11-10/td-p/216792/page/3 )

To fix this for skype in the launcher, make sure Skype is not running. 
Then run this command at the terminal: 
   sudo gedit /usr/share/applications/skype.desktop
This opens the shortcut for skype in a text editor so that you can change it. 
Change the exec line to look like this (32-bit): 
   Exec=sh -c 'LD_PRELOAD=/usr/lib/i386-linux-gnu/libv4l/v4l1compat.so /usr/bin/skype "$@"' 
Now test.