In 2003, the Harvard biologist E.O. Wilson wrote a widely read essay that called for an "Encyclopedia of Life." Summed up simply, Wilson had in mind "an online reference source and database" that catalogued "every one of the 1.8 million species that are named and known on this planet," not to mention the many organisms that aren't yet known. When fully compiled, the web-based database would offer a "macroscope" of sorts, a way to do comparative biology and ecology on an unprecedented scale, allowing scientists to gain new insights into the immense biodiversity of our planet.
Wilson is still pushing this vision, and he laid it out most recently at the TED Talks conference in Monterey, California. (Watch the video below.) The envisioned encyclopedia will be a collaborative enterprise, modeled somewhat along the lines of Wikipedia (see some demonstration pages here). And it'll be accessible anywhere, anytime, to whoever could benefit from it. It's expected to take close to a decade to complete the project, although some key components of the database will be available in 2008. (See this FAQ for more details.)
For more information on E.O. Wilson, I would encourage you to listen to Bill Moyers' profile of Wilson (iTunes - Feed - MP3) which recently aired on PBS. You may also want to give some attention to Wilson's latest book, The Creation: An Appeal to Save Life on Earth.