Mathematical Tools at MIT: Introduction to MATLAB®, class materials that were originally developed for a hands-on training course offered by the Office of Educational Innovation and Technology (OEIT) at MIT.
Introduction to MATLAB, class materials that were developed by Yossi Farjoun of the MIT Department of Mathematics for a non-credit program during MIT's Independent Activities Period. A collection of additional MATLAB resources are also linked from this web site, including teaching codes and tutorials.
MATLAB demos by Mathworks
MATLAB Primer: A tutorial by Dr. Kermit Sigmon, Department of Mathematics, at the University of Florida
MATLAB resources at Indiana University
A Practical Introduction to MATLAB by Mark S. Gockenbach, Department of Mathematical Sciences, at Michigan Technological University. These notes are a good starting point. The section on "Simple calculations and graphs" is particularly appropriate for help in getting started.