Where to get Mathematica student copy: http://computing.cos.gmu.edu/mathematica/
The GMU Virtual Computing Lab can be accessed here: https://www.vcl.gmu.edu
A good introduction to Mathematica (written by HS students) is here: http://math.sduhsd.net/MathematiClub/tutorials.htm
The main Wolfram site for information is: www.wolfram.com