LabVIEW

This is one of the most powerful tools I have learned. The given link provides an excellent tutorial for it.

http://www.mech.uwa.edu.au/jpt/tutorial/ieindex.html

Latex

Latex is a really powerfull tool for doing scientific documentation. I learnt it from this website. Its really nice because the actul tutorial is itself in Latex so one gets a hands on experience while learning it.

http://www.math.rug.nl/~ernst/latex/