1) General Chemistry (no website name found)
This website has a wide selection of topics and is very easy to use. Diagrams are of poor quality but topics are well explained. The website is not at all attractive but very functional and loads very quickly even with dial-up. There is one non-functional link but the rest makes up for this(who wants to know about polymers anyway:)).
2) Physics Encyclopedia: General Physics Resources
Although this site is named differently, I will include it in both of the science sections. It does seem to be more chemistry orientated but due to the astrology aspect I will keep it in the physics section as well. For a review see the physics page.
Insanely fast to load even with dialup. Gives a range of basic topics on physics or chemistry that seem to explain well. Attractive for a small, fast website as it is.