Light and Matter - Free introductory physics textbooks for the high school or college level, available as large pdf files to download. Topics available are Newtonian physics, conservation laws, vibrations and waves, electricity and magnetism, optics and modern physics. Maxwells Equations and Electromagnetic Waves - A lecture from professor Michael Fowler at U of Virginia. Long and detailed. Particles, Special Relativity and Quantum Mechanics - Explains some of the more interesting results and predictions of modern physics.
All lecture notes are online, and include material on relativity and quantum theory.
Physics Tutorials - Math and some basic physics concepts requiring math or understanding of vectors. All topics can be downloaded as word files. Large file to download. Students - Geared towards teachers so they can in turn teach others about superconductivity. Detailed, and a good read for anyone interested in the topic.