I'm sure this is a FAQ type question that there is a standard answer for, but for me the resources that are good are:
http://www.stat.sfu.ca/~cschwarz/Sta...ts/node62.html and related links for one of the clearer explanations of commonly used statistical terms and how to apply them.
For more math question obscure or common I find
http://mathworld.wolfram.com/ has a done of information.
Hope that helps.