Physics Organizations
The Americal Institure of Physics (AIP)
The American Physical Society (APS)
The American Association of Physics Teachers (AAPT)

Physics, Engineering & Mathematics Departments
Web Sites - Links to departments and institutions within/outside the U.S.
(Waubonsee Community College compilation)

Technical Data and Other Information:
Physical Constants
The Periodic Table 
Atomic Mass Data
Table of Nuclides
Review of Particle Physics from LBL
SPIRES Library Database from SLAC
E-print Archive from Los Alamos
CERN Preprint Service