How to apply webcam effects to other applications?
Solution 1:
There is a program called "WebcamStudio" which should do exactly what you are asking.
https://sourceforge.net/projects/webcamstudio/
Solution 2:
The project is continuing on google code here:
http://code.google.com/p/webcamstudio/
There you can also find a ppa for daily builds, so you do not need to compile it yourself:
https://launchpad.net/~webcamstudio/+archive/webcamstudio-dailybuilds