We talked with the guys of Teamspeak about the new features and future plans. The core was completely overworked and the client and server version runs now on Windows (32 and 64bit), Mac OS and Linux. TeamSpeak 3 also includes a robust cross-platform Software Development Kit (SDK). The security level and privacy was improved. The GUI (Graphical User Interface) has been completely redesigned and is now fully customizable.
More information and details you find here:
http://www.teamspeak.com/?page=teamspeak3