Finding information and resources on the internet that are relevant to you can be a difficult task. The problem is not a lack of information but too much of it!
The following are links to sites that may help you with your study of mathematics:
Math.com - World of Math online
Ask Dr Math
To find resources for particular science topics it is often easier to use a directory such as the Google Web Directory which has webpages sorted into relevant categories, for example science educational resources