Madonna and Microsoft has launched today a new charity single for the environmental campaign Live Earth, a monumental music event, which will bring together more than 2 billion people to combat the climate crisis

Madonna’s new song, entitled “Hey You� was written exclusively for the Live Earth concert series and it can be downloaded for free on liveearth.msn.com through May 24. For the first 1 million downloads, Microsoft has pledged to donate 25 cents to the Alliance for Climate Protection. Live Earth concerts will be streamed live on July 7 (7/7/07) at LiveEarth.MSN.com. The July 7 show will take place in London, New York, Sydney, Shanghai, Tokyo, Johannesburg, Rio de Janeiro, Istanbul and Hamburg.

So far, only the US, UK and Australian lineups have been revealed, with organizers promising to release additional artist rosters in the coming days.

Bon Jovi, Sheryl Crow and Kanye West are among the acts playing Giants Stadium outside New York, while the Red Hot Chili Peppers and the Black Eyed Peas will join Madonna at London's Wembley Stadium. Crowded House, Jack Johnson and Wolfmother lead the lineup at Sydney's Aussie Stadium

"The early release of Hey You is an incredible boost to our efforts to get people engaged in the environmental cause," Live Earth founder Kevin Wall said in a statement. "We are thrilled that Madonna donated her art to Live Earth and is a part of this movement for us."

Beside Madonna’s single, the new LiveEarth.MSN.com site includes videos, photos galleries, and information about Live Earth artists and venues. People can watch videos of the various Live Earth venues, download Live Earth-themed wallpaper and other customization features, and join Live Earth communities.

“At MSN, we want to offer people amazing media experiences, like this exclusive song from Madonna and our Live Earth site, that not only inspire, but entertain,� said Joanne Bradford, corporate vice president and chief media officer of MSN. “As the exclusive online partner for Live Earth, we are able to give our 465 million monthly users an exciting and interactive experience that will educate people about climate change and encourage people to take action.�