Mark, You suggested that I try sipc as an alternative to Windows Messenger. Sipc sounds like a great program since it has add-ons for voip, video, and whiteboard, as well as support for STUN. Sipc is also free for educational and research users. But I am not sure that my for-profit tutoring service would qualify as an educational organization. So I contacted Sipquest.com about pricing for a commercial license. They sent me to 3Com, who is supposed to be using sipc in their VCX product for "medium to very large businesses". The 3Com saleguy said he had never sold sipc to anyone, but he would pass my name to a company called Parallel Technologies which is considering creating a SIP server and might be planning to use sipc as a client. In summary, it appears that the commercial version of sipc is not available right now. I will try to get a free educational copy of sipc, just to evaluate it. thanks Michael