Science Daily — Breaking scientific news and the latest scientific discoveries.
How Stuff Works — Site with explanations and colorful illustrations related to earth science, life science, and other wonders of the physical world.
Scitable — Science library that acts as a classroom resource as well as a personal learning tool.
Space.com— Massive repository of information on the heavenly bodies, including space flight missions and space-related technologies.
Scientific American — One of the most thorough resources available online for learning and teaching science.
Livescience — Website features groundbreaking developments in science, space and technology.