SIP-based Ad-Hoc Conference

I just found a company, Pangean Technologies http://www.pangeantech.com that those something like a “IM with Voice” and you can do Dynamic group conference, Push to talk, IM, etc.

However, they are enterprise-based so you need their server and stuff. Does anyone know of a regular consumer based product like this?

By the way, Messenger won’t work because there is no Dynamic conference.

Thanks, Akim