It was recently revealed that UK Xbox Live Gold account owners will be able to use Twitter and Facebook through Xbox Live.
A “Friends Linker” will allow you to invite Facebook friends to play on Xbox LIVE, and also allow you to see full screen pictures of them, whilst you will be able to read and post updates on Twitter and keep up with friends and news in real time.
The services are set to launch on November 17th 2009 along with “loads more exclusive content”
Visit here for more details: http://www.xbox.com/en-GB/social/
NOTE: US release should be around this time period.