Wolfram Research
Wolfram Math World: Spherical Coordinates
This site provides a general overview of spherical coordinates, the system of curvilinear coordinates which describes positions on a sphere or spheroid.
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.
Other
Dans Math: Lessons: Calculus (Part 2)
College professor Dan Bach offers a review of the calculus concepts of integrals and vectors. Examples and animated graphs are provided.