Spark 2.6.0 Beta 2
Spark is a free, cross-platform IM client optimized for businesses and organizations. It features built-in support for group chat, telephony integration, and strong security. It also offers a great end-user experience with features like in-line spell checking, group chat room bookmarks, and tabbed conversations.
Combined with the Openfire server, Spark is the easiest and best alternative to using un-secure public IM networks. Spark also works with Spark Manager, so that all IM clients in your network can be easily provisioned and managed.
Spark works great on Windows, Mac OS X, Linux and Unix.