Go to logitech.com,, and chat with the online tech. Good Luck
The first link below appears to have source code for a video conferencing demo that uses VOIP. Also there's a library on SourceForge that has lots of source code and demos for interfacing C# to DirectShow, might be worth a look. Good luck!
Hiya :) You can get on eBay a used Logitech QuickCam Pro 3000 which is an excellent web cam. I bought one for under $25 and it works PERFECT! You may also want to try using iVisit video conferencing once you've got your cam, it's great and FREE!