There's a live press conference you can watch on the Huffington Post right now in which NASA scientists are discussing their findings. It seems that the polar regions of Mercury seem to have a lot of water, and possibly organic matter.
UPDATE 11:35 AM: NASA is now taking questions directly from the public via social media. You can find more information about this discovery at Space.com:
Temperatures on Mercury can reach 800 degrees Fahrenheit (427 degrees Celsius), but around the north pole, in areas permanently shielded from the sun's heat, NASA's Messenger spacecraft found a mix of frozen water and possible organic materials.
The first question was about what this means for the possibility of some sort of life on Mercury. The scientist answering the question says "the more we learn about the solar system, we find it's a soggy place." "Let me be clear that no one is saying that there is life on Mercury," a killjoy explains, but he says "Mercury is becoming" a site for "astro-biological interest" and "in terms of the book of life, there are some early chapters" and "Mercury is helping us answer those questions" in those early chapters.