There are many great resources available on the world wide web if you have a math question. Be nice to these people- they're providing a great service to all students. At most of the sites you can check questions that have already been asked so you can get a quicker answer, and avoid bothering the experts too much.
Your best bet may to visit our math message board where you will find numerous experts ready to answer your questions. While many posts are answered in just hours, there is no guarantee. Remember, everyone is a volunteer.
Ask Dr. Math - This is probably the best resource out there for anyone wanting an answer to a math question. Search their archives first to see if your question has already been asked, and then ask your own to Dr. Math.
Ask MathNerds.com - A large group of math experts have banded together to provide this excellent service. Ask these people your math questions and you're sure to get a quick, correct answer.
Gomath.com - This site has tutors available to answer your math questions for free.