Type math formulas in Microsoft Word using LaTeX

You can use Latex in Word 
(http://latexinword.sourceforge.net/)
It provides macros for Microsoft Word that allow the use of LaTeX input to create equations images in both inline and display modes without having to install any software on the local computer. As far as I know, this is the only free alternative to the paid programs like Aurora and TexPoint.

For Office 2007, go to Latex in Word Project Page on Source Forge, and click on Word 2007 underFiles.

LaTeX in Word is a GPL-licensed tool that allows equations to be used in Microsoft Word documents. The client-side of the program is implemented as VBA macros in the document "LaTeXinWord_v_0_3_1.docm" along with instructions. Hence, this file contains the source code, implementation, and documentation.

You can use TeXsword
(http://sourceforge.net/p/texsword/wiki/Home/)

TeXsword over Latex in Word (http://sourceforge.net/projects/texsword/). It has all the features of Latex in Word, plus gives handling of equation references. And it doesn't require the Internet connection, which I see as a feature not a limitation: MikeTeX isn't that big after all, and having the LaTeX locally allows you typing your document when traveling.

You can use VBA Latex equation

http://sourceforge.net/projects/vba-latex-eqn/?source=navbar

VBA Latex Equation contains a series of VBA macros for generating png latex equations in MS Word document, which is a potential replacement of MathType and Aurora.

LaTeX in web page use MathJax

http://superuser.com/questions/340650/type-math-formulas-in-microsoft-word-the-latex-way