The NIST Reference on Constants, Units and Uncertainty Values recommended for international use by the Committee on Data for Science and Technology, International Council of Science. Navigation is by text search. http://physics.nist.gov/cuu/Constants/

The Laws List An alphabetical glossary of the various laws and theorems in this science. http://www.alcyone.com/max/physics/laws/

Physics Formulae A collection of frequently used physics equations compiled into several downloadable formats. http://www.xs4all.nl/~johanw/contents.html

Physics FAQ (Where to Find It) Links where to find the FAQ documents for physics. http://www.faqs.org/faqs/physics-faq/where-to-find-it/

Eqndb Search for physics equations and constants by keywords and symbols. http://www.eqndb.com

The Physics Reference Site contains every forumula a first-year physics student is likely to run into. http://dph1701.tripod.com/physsci/index.html

Physics & Astronomy Discussion Forums Discussion forums devoted to physics & astronomy, with a concentration on eletricity and magnetism. http://physicsastronomy.com/