WinMerge is an Open Source (GPL) visual text file differencing and merging tool for Windows.It is highly useful for determing what has changed between project versions, and then merging changes between versions.

Features

* Visual differencing and merging of text files
* Flexible editor with syntax highlighting, line numbers and word-wrap
* Handles Windows, Unix and Mac text file formats
* Unicode support
* Difference pane shows current difference in two vertical panes
* Location pane shows map of files compared