Chatter Desktop is a free desktop application that lets you collaborate in Chatter without a browser. Use Chatter Desktop to post and comment in Chatter, and receive updates about your groups and the people and files you follow. Chatter Desktop also supports chat, private Chatter messages, and displays Chatter updates and private messages as popup notifications in your Windows taskbar or Mac OS X Dock.
At the top of any page, click, then click Chatter Desktop. To install, click Download Now and follow the on-screen instructions.