Wolfram Research
Wolfram Math World: Dot Product
This math site gives the formula for taking the dot product of two vectors, gives properties of dot products, (commutative, associative, and distributive), how to find the derivative of a dot product. This site has links to several other...
Wolfram Research
Wolfram Math World: Vector
This site from Mathworld.com provides a detailed overview of vectors in algebra, and includes numerous formulas and examples.