Hello, I need to setup a small voip system for a handful of people. In a nutshell I would like these people to logon with a sip softphone and join a conference call. It would also be nice to have the call encrypted.

OpenSER looks like it fits the bill on the server side and I will building and playing with a bit later, but outside of MS Messenger are there any other clients out there? I need clients for Windows, Linux and MAC.

Many thanks.

Gary.