WinDiff - Download Windiff : free files and folders comparison tool
WinMerge - WinMerge is an open source differencing and merging tool for Windows.
Text compare! - Text compare! is a online diff tool that allows you to easily spot the differences between to texts.
AptDiff - AptDiff is a visual text / binary files comparison and merging utility for Windows.
Plagiarism Compare - Free plagiarism checker to compare two texts side by side, highlight similarities, and detect duplicate content.
Compare - Download Notepad++ Compare plugin for free. Comparison plugin for Notepad++ editor. Comparison plugin for Notepad++ editor.