free instant messaging

Business messaging reinvented.

Encrypted BBS style client for chat, messaging, and transfers.

Native OS X desktop client for the Yammer messaging service.

Enterprise messaging/collaboration software.

Internet phone and instant messenger (was SIP Communicator).

Organize instant online meetings with HD video conferencing and content sharing.

Encrypt instant messages with Open-Source security.

Secure instant messenger.

OpenC6 is a Linux and Mac OSX free instant messenger.

Video conferencing and instant messenger.