Jitsi (previously SIP Communicator) is an audio/video and chat communicator that supports protocols such as SIP, XMPP/Jabber, AIM/ICQ, Windows Live, Yahoo!, Bonjour and many other useful features. Jitsi is Open Source / Free Software, and is available under the terms of the LGPL.
The application is developed (mostly) in Java and basd on OSGi.
http://www.jitsi.org/
Tropo is an application platform that enables web developers to write communication applications in the languages they already use: Groovy, Ruby, PHP, Python and JavaScript. Tropo is in the cloud, so we manage the headaches of dealing with infrastructure and keeping applications up and running at enterprise-grade. Tropo is simple to deploy, requires no contracts and no up-front setup costs. With Tropo developers can build and deploy voice and telephony applications, or add voice to existing applications.
Previously developers had to write voice applications in VoiceXML. This has left out developers who either did not want to learn VoiceXML, wanted the flexibility of working in other development languages or have been working in VoiceXML for 10 years and are ready for a change.
