"Overwolf is a FREE software client which brings your life into your games. It seamlessly integrates social media tools like Facebook, Twitter, Skype or MSN Messenger in order to help you share game experiences and connect with your friends while playing."
"Launch Overwolf and start your game. Once you are in game, simply move the mouse cursor above Overwolf widgets to control them. If no cursor is available, for example when playing a First Person Shooter, hit Shift+F1 to control Overwolf, and Shift+F2 to show/hide Overwolf. You can configure your own personal hotkeys in the settings window."
More info can be found at http://www.overwolf.com/Faq/
The program is currently in beta, so users might bump into a few issues:
1. It may not work properly if you open it AFTER you open the game
2. Might lack the proper adobe flash player, check http://get.adobe.com/tw/flashplayer/ and hopefully it can work out
3. Does not seem to support Windows XP
4. Uncompaitable with MSI Afterburner