List of Science Museums by Dept. of Energy.
Inquiry Learning through some science museums, by the Science Learning Network.
Hands-on Science Centers Worldwide. Lists of museums, some with reviews.
Science Museums and Exhibits. Lists of science museums with online exhibits, ones with historic instruments, links. From U. Washington.
Exploratorium. The best museum in person or online! Many interactive explorations, webcasts, things to make at home, etc.
Franklin Institute Online. Photos, text, and experiments to do.