Skype does not work well with newer version of GSPCA Webcams driver (Linux Kernel >=2.6.27), possible workaround:
 * Ubuntu 32 bit: install "libv4l-0" package and launch Skype with: LD_PRELOAD=/usr/lib/libv4l/v4l1compat.so skype
 * Ubuntu 64 bit: install "lib32v4l-0" package and launch Skype with: LD_PRELOAD=/usr/lib32/libv4l/v4l1compat.so skype

https://developer.skype.com/LinuxSkype/ReleaseNotes

http://www.gentoo.ru/node/13419