American Museum of Natural History has a clean, elegant design that parallels the look and layout of the museum's renovated halls of vertebrate evolution. The site may tax the technological capabilities of those running slow connections or old Web browsers, however.
Smithsonian Institution site marks the entry point to the vast and varied parts of the Smithsonian: 16 museums and galleries, the National Zoo and sundry research facilities. Skip the guided tour--the opening screen tells you everything you need to begin exploring.
The Franklin Institute Science Museum augments online exhibits with news stories, hot links and other useful resources.
The San Francisco Exploratorium translates some of the museum's hands-on feel to the electronic medium. The tutorials are aimed broadly at both parents and children, the science-curious as well as educators.
The Science Museum, London conveys a British feel even on the Web. Floor maps and images reside in the "collections and galleries" section.
UC Museum of Paleontology, part of the University of California at Berkeley, maintains one of the best life-sciences collections on the Internet. It includes in-depth discussions of evolution and a detailed, illustrated tree of life; the dinosaur section is outstanding.
- Hands on Science Centers Worldwide - Science Museums have the coolest websites. Here they all are, all at once. Take it slow, don't get brainburn.