I have been using the verbosely named Microsoft Outlook Connector Provider for Facebook (MOCPF?) for the past month and thought I would pass it along. It offers integration with Facebook for anyone registered with an email address in the GAL or your contacts. If you are a Facebook friend with the person it also offers you status updates. It apparently works with Office 2003 and 2007 as well, with an additional piece of software. Here is a screen shot of the integration in Outlook 2010.
There are connectors for a few social providers out there. Here is the list I was able to find:
