For help in using your TI-83 or TI 84 calculator, visit MathBits.com:
Good written resource explaining many specific algebra concepts.
Khan Academy has produced short videos that explain most any math concept with which you might need help. On the Khan Academy home page, click the "WATCH" link, select "MATH" and then select they type of math you are learning (Arithmetic, algebra, geometry, etc). Then scan the list of math concepts in that category to find one that will help you.