Get started with iMessage for OS X | How To – CNET http://howto.cnet.com/8301-11310_39-57379309-285/get-started-with-imessage-for-os-x/
iOS 5 features: iMessage brings free texting to iPad, iPod touch | TUAW – The Unofficial Apple Weblog http://www.tuaw.com/2011/10/12/ios-5-features-imessage-brings-free-texting-to-ipad-ipod-touch/
How to Set Up & Use iMessage on iPhone, iPad, & iPod touch with iOS http://osxdaily.com/2011/10/18/set-up-imessage-on-iphone-ipad-ipod-touch-with-ios-5/