Two-party video conferencing

[Ben Scott]

Hey,

  I've been asked to look into video conferencing.

Requirements:

R1. Two parties only.  (Not a "big table" meeting.)
R2. Completely in-house.  No big server in the sky coordinating or
routing traffic.  Everything has to stay behind our firewall and
inside our VPN.
R3. Has to support Win32 clients (but running it against our Linux
server would be cool).

  What I'd like to avoid is being forced to adopt yet another
proprietary, expensive, Windows-only solution, that only further
serves to tighten Microsoft's grip on us.  So ideally I'd like an
"free as in freedom" solution.  FOSS server and client, cross-platform
implementation, open protocol.  Of course, that might not exist.  I'm
not against paying for a good solution, it's just that one so very
rarely finds a solution worth paying for.

  Anyone have anything they can share WRT the above?  Knowledge,
ideas, recommendations, things to avoid?

  It's unclear to me if Pidgin *requires* Google for video
conferencing, or if you can run your own server.  It's also unclear to
me if the video conferencing client can even run on Win32.

-- Ben