For helpful links, click below...
Click here to see some applets to visualize concepts
Click here for some Mathematica notebooks on MV calculus.
Go to Animated Demonstrations for Multivariable Calculus to see cool animation.
Thanks to Paul Blanchard (From Boston U.), you can use interactive applets.
Get a freeware, from graphcalc.com, of a graphic calculator for your computer. This graphic calculator plots in 3D.