"Every few months or so I go looking for another free diff tool that I like as much as WinMerge (usually in vain) since WM hasn’t released a new version in over 2 years. WinMerge 3, while having been in planning for almost as long, still hasn’t seen any real development traction.
Today however, I was surprised to stumble across a fork of the WinMerge 2 code base that seems to be in active development under the name of WinMerge 2011. There have been a couple of releases so far and the developer seems to be one of the WinMerge developers (Jochen Tucht) as they have commits in the official WinMerge SVN repository.
The WinMerge 2011 series is a fork of the original WinMerge application published on SourceForge by Thingamahoochie Software. It is an escape from the complex situation (http://shortlinks.de/ce1j) that exists with respect to WinMerge 2.x. ATL/MFC dependencies have also been removed so as to enable zero-budget developers to build WinMerge from sources using Visual C++ Express editions.
From the Readme;
WinMerge is an Open Source comparing and merging tool for Windows. WinMerge can compare both folders and files, presenting differences in a visual text format that is easy to understand and handle. WinMerge can be used as an external differencing/merging tool or as a standalone application.
WinMerge has many helpful supporting features to make comparing, synchronising, and merging as easy and useful as possible. Several programming languages and other file formats are syntax-highlighted.
The nice thing about WinMerge 2011 (and WinMerge 2.x) is that it's OSS (C++)... I always appreciate the chance to look behind the curtain (if I so desire)