Last Spring Microsoft added support to have Xbox Live users to link their Live account to their Hotmail instant messenger friends list.  This functionality became nice way to liink your IM friends to their Xbox Live accounts.  Now from your computer you can send IMs to people playing on their 360s.  This is an easy way to setup games with your friends that may either be on their 360 or their PC.

Since using the 360's on screen keyboard is not the best way to send instant messages, Microsoft announced the Chatpad.  The device is a small keyboard that clicks into your controller.  It is now coming to stores September 4th.  I've got a couple links below that talk about the device and adding instant messaging to the Xbox 360.


http://www.xbox.com/en-US/community/news/2007/0408-im.htm
http://www.xbox.com/en-US/hardware/x/xbox360messengerkit/
http://unboxing.gearlive.com/