International Call Guide Save money on international phone calls with Dial Around, VoIP, Calling Cards, PC to Phone or International Callback. http://www.call-guide.com
Web pages:
Eric Weisstein's Treasure Trove of Physics Online encyclopedia of physics terms and formulas. Full searchable, and also browsable alphabetically and by topic. Part of Eric's Treasure Troves of Science. http://scienceworld.wolfram.com/physics
Physics and Astronomy Classification Scheme (PACS) Hierarchical numbering scheme, developed by the American Institute of Physics, used to identify fields and sub-fields of physics. http://publish.aps.org/PACS
Physics Central A page on modern physics, such as quantum mechanics and black holes, and some mathematics. http://www.physlib.com
Physics News Graphics Diagrams (with captions) appearing in various AIP publications, sorted by category or by date. http://aip.org/mgr/png
Physics Post A tutorial and article driven community. Votes, science news and a discussion forum. http://www.physicspost.com