In order to help, we would need some more specific information. What kind of routers are you using? What specifically about video conferencing are you looking for?

I have linked a few sites that maybe of help if you are dealing with Cisco routers.

http://www.swcp.com/~jgentry/topo/cisco.htm

http://www.cisco.com/univercd/cc/td/doc/product/rtrmgmt/netsys/netsysrg/ciscortr.htm

This last link is to an article by David Davies a fellow TechRepublic writer and a very knowledgeable resource for Cisco equipment.

http://blogs.techrepublic.com.com/networking/?p=419