"Imagine an electronic page for each species of organism on Earth..." - Edward O. Wilson
Encyclopedia of Life is an online encyclopedia project that aims to capture information about all 1.8 million named plant, animal, and fungal species on Earth within ten years. They've made a good start, with more than 170,000 species described so far. The project combines a wiki/Web 2.0 approach of public contributions with expert curation by scientists. Searching is quite flexible, by either species name, tags, or full text or by drilling through taxonomy. Contents include species descriptions, distributions, images, comments, and metadata.
The Field Museum of Natural History, Harvard University, Marine Biological Laboratory, Smithsonian Institution, Biodiversity Heritage Library, Missouri Botanical Garden, and Atlas of Living Australia are partners in the project. The project is funded through grants from the MacArthur Foundation and Alfred P. Sloan Foundation.
The encyclopedia works as both a field guide and a "macroscope" that can help discover patterns in ecology and evolution otherwise too large or too complex to perceive.