Desktop application for facebook messaging. Very useful for people who use facebook for chatting (I know I do.)
Here're the goods-
download facebook messenger for windows

From the help page:
Messenger for Windows is a new, trial application that lets you use Facebook without being on www.facebook.com. While you surf the web or use other applications on your computer, you can:

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  • Chat and message with your friends on Facebook
  
  
  
  

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  • See the latest updates from your friends in ticker
  
  
  
  

• Get quick notifications about what’s going on

more information on the facebook helpdesk