Here are some useful links that provide great resources that are related to math.
Wolfram Alpha – Never do homework again! Just be careful, you’ll fail your final if you depend on this too often.
Paul’s Online Notes – Better than some professors! Great resource for Calculus, Differential Equations, and Linear Algebra. Material is very similar to the courses, and a great resource if you’re confused on certain topics.
arXiv.org – New math, physics, and computer science papers.
Here are some useful links that will waste your time and/or not help you with math in any way.
omfgdogs – dogs.
Friday – Click this if today is Friday
xkcd – fun comics
smbc – more fun comics
Kevin’s blog – self explanatory