MathType - The Professional version of Equation Editor- MathType is a powerful interactive tool for Windows and Macintosh that lets you create mathematical notation for word processing, web pages, desktop publishing, presentations, and for TeX, LaTeX, and Math…
NumWorks - The graphing calculator that makes learning math easier.
Math-o-mir - The Mathematical Notepad.
Learney - Knowledge aggregator for developers
Math Magic - MathMagic Equation Editor for Desktop Publishing software & Word Processors, Adobe InDesign, QuarkXPress, MS Word, iWork, for Technical writing with very easy interface and fast input.
eMathHelp.net - Site is created to help people learn math. Includes algebra, calculus, differential equation calculators and notes with many examples.