Thanks for your interest
Concombre is free software so you can use it as you wish in aMsn if you think that it is interesting
The software is curently based on OpenCV (Open Computer Vision - http://sourceforge.net/projects/opencvlibrary/
). This library permits to make many operations of professionnal industrial vision (that's the way I use it in my job) but also to produce funny effects.
The library gives you an environnment to work on images and stream, in the case of concombre I have to load a xml classifier (for human faces the file is availlable in OpenCV source code), apply a function to your current webcam image, then you get position/size of faces. Then you copy your template. You can also make your own classifier, but it is very long : 3-10 days of computing.
OpenCV is also able to produce many other effects like motion vector detection in a stream, blob tracking...
For the moment concombre uses /dev/video0 via the OpenCV webcam interface but I have a development version witch uses directly ioclts.
If the concombre feature interrests you I can contribute to the aMSN project as you want : creating a library witch take RGB data plus configuration structure , do the job and sent RGB data.
I have planned to make such a libconcombre to serve other applications.
Let me know how I can help aMSN project
EDIT : yes concombre is a project of my own, but many people of debian-fr.org have contributed to make it works !