Khan Academy: A highly interactive site providing over 3,000 free video tutorials and exercises covering a range of subjects--math, biology, chemistry, physics, and much more.
Wolfram Alpha: A fundamentally new way to get knowledge and answers--not by searching the web, but by doing dynamic computations based on a vast collection of built-in data, algorithms, and methods. Covers mathematics, words and linguistics, history, science, computational sciences, money and finance, just to name a few.
Stewart Calculus: A resource for calculus help.
The Purdue Online Writing Lab: This site contains over 200 free resources offering assistance with the writing process, conducting research and appropriate use of grammar and citations.
The Writing Center (UNC): A collection of detailed handouts covering all elements of writing: pre-writing, paper development, thesis construction, citations, style, and writing for specific fields.
The Assignment Planner: An online tool to help you manage and locate resources related to research and writing. Enter today's date, and the date your assignment is due, and you will receive a time management calendar with links to resources and target completion dates for each phase of your research project.
Study Guides and Strategies: Techniques to help you with managing time, tasks and projects, motivating yourself, solving problems and making decisions.
The Math Forum at Drexel: Browse questions and answers for a variety of math topics.