LaTeXiT is not available for Windows but there are plenty of alternatives that runs on Windows with similar functionality. The best Windows alternative is KLatexFormula, which is both free and Open Source. If that doesn't suit you, our users have ranked more than 10 alternatives to LaTeXiT and 11 are available for Windows so hopefully you can find a suitable replacement. Other interesting Windows alternatives to LaTeXiT are TexMaths (Free, Open Source), MathType (Paid), EqualX (Free, Open Source) and Apache OpenOffice Math (Free, Open Source).
TexMaths is an addon designed to provide LaTeX support into LibreOffice. LaTeX equations can be inserted as images (SVG or PNG formats) and the LaTeX code is saved into the image attribute for further editing.
MathType is a powerful interactive equation editor for Windows and Macintosh that lets you create mathematical notation for word processing, web pages, desktop publishing, presentations, elearning, and for TeX, LaTeX, and MathML documents.
Math, part of the Apache OpenOffice suite, is a tool for creating and editing mathematical equations, similar to Microsoft Equation Editor (included in Microsoft Office). The created equations can then be embedded inside other OpenOffice.
This tool provides a very simplistic gui that renders LaTeX-expressions directly while typing and is able to copy the rendered images to the clipboard or alternatively save them to the desktop while maintaining transparency information.
RedCrab Calculator is a mathematics software with fullscreen editor for the free placement of algebraic formulas on the worksheet in mathematical notation. Results can be displayed in different numeric formats and in diagrams. Images and texts can be inserted.