Teaching American History is a good social studies website for anyone who needs to know something about the history of America or needs some good primary resources.
The Avalon Project is a project by Yale University to get primary resources for students. On the site, there is historical documents in text form. This is extremely useful for social studies.
Tutsearch is an online tutorial website. It has tutorials for anyone who needs help with a certain subject. It is especially helpful for anyone in college or a senior who is looking for a path.
Quicklyst is an easy to use tool to help you take organized notes. It is nice because it does not bug you with programs, it is a simple program that will help.
Geogebra is a graph making tool/website. With this, you can create graphs of any kind, and learn how to figure out slope. This tool is great for figuring out things about lines and graphs
This site is a big science article site. The company is famous for its long running magazine (125 years, to be exact), and you can probably find an article on its website.