Some Resources on the Internet
From Niserwiki
The following link is a good read and guiding material for anyone who wishes to be a mathematician. Note that the author writes it from the US perspective but yet it is applicable in a general manner. The thread's title is Who wants to be a mathematician?
Are you interested in the History of Mathematics and Mathematicians? Surf the following website The MacTutor History of Mathematics. It contains biographies of mathematicians, history topics, famous curves and many additional materials.
Resources on Leonhard Euler: The following website contain most of the works of Euler along with commentaries. The Euler Archive
Latest pre-prints and archives (arXiv is an e-print service in the fields of physics, mathematics, non-linear science, computer science, quantitative biology and statistics) arXiv
S.O.S. MATHematics is your free resource for math review material from Algebra to Differential Equations! SOS Math
Numbers, Constants and Computation, a very nice resource on the web Numbers, et al
Of course, Millennium Prize Problems
Interactive Mathematics Miscellany and Puzzles Cut-The-Knot
Series, Pi, etc [1]
The Math Forum @ Drexel University
The Fermat Last Theorem Blog (With proofs) [2] And if want to tackle the whole proof yourself click here Fermat Last Theorem
Resources for Undergraduates [3]
More exhaustive list of mathematics websites over here [4]
Eric Weisstein's World of Mathematics [5]
The On-Line Encyclopedia of Integer Sequences [6]

