There are many customers who deployed Microsoft Office Communicator on XenApp for instant messaging, presence info & audio conferencing. And with the XenApp 6 release, we introduced a new HDX RealTime feature that enables customers to host Microsoft Office Communicator on XenApp servers and enable end users to use their web cams for video conferencing.
Though we have targeted Office Communicator video conferencing with XenApp 6 release, this feature leverages DirectShow technology that is part of the Windows OS and hence any video conferencing application that is built using DirectShow (e.g. Skype) should just work. This feature does require the latest 12.0 online plug-in/client. Regarding bandwidth usage, our internal testing has shown around 300Kbps-600Kbps upstream traffic and around 800Kbps-1Mbps downstream traffic. And we have seen good performance even with 200ms round trip latency connections! Regarding scalability, doing video conferencing does have a scalability impact on CPU and we have seen good performance with up to 10 active video conferencing users on a dual quad core server.