I just came across this i'm program from MSN Window Live Messenger.
"i’m is a new initiative from Windows Live™ Messenger. Every time you start a conversation using i’m, Microsoft shares a portion of the program's advertising revenue with some of the world's most effective organizations dedicated to social causes. We've set no cap on the amount we'll donate to each organization. The sky's the limit.
This is only available in US now. But as long as you have MSN Messenger, the i'm icon will be shown. If you are in US but don't have Messenger and want to participate, simple click on the icon and it will link you to the home page!
Start to make a difference: