Mathcad

BarBuilder
A plugin for MathCAD that renders transparent 3D bars.
http://www.geocities.com/udodenko/barbild.html

Introduction to Mathcad
Teaches basic Mathcad skills, including graphing, solving, and annotation. Designed for students and for Mathcad 6 and above.
http://www.monmouth.edu/~tzielins/mathcad/tjz/doc001.htm

Mathcad at Adept Scientific
Links to free downloads, application files, education files, technical support files, and updates to Mathcad.
http://mathcad.adeptscience.co.uk/

Mathcad Collaboratory
Official online forum for Mathcad users. Provides a means to share tips and worksheets for using Mathcad in many engineering and scientific disciplines.
http://collab.mathsoft.com/~mathcad2000/

Mathcad Mailing List Archives
Archives of the Mathcad email list, a worldwide discussion group, with gripes, suggestions, and lots of tips and solutions from Mathcad users.
http://lists.adeptscience.co.uk/mathcad/

MathParser
A utility that parses Mathcad's MathML output into LaTeX.
http://www.tilman.de/mathparser/index_en.html

SCIA Scientific Software
Official Mathcad distributor for Belgium and Luxembourg. Products and services.
http://www.mathcad.be/