WinMerge:
* Visual differencing and merging of text files
* Flexible editor with syntax highlighting, line numbers and word-wrap
* Handles DOS, UNIX and MAC text file formats
* Unicode support
* Difference pane shows current difference in two vertical panes
* Location pane shows map of files compared
* Highlights differences inside lines in file compare
* Regular Expression based file filters in directory compare allow excluding and including items
* Moved lines detection in file compare
* Creates patch files
* Shell Integration (supports 64-bit Windows versions)
* Rudimentary Visual SourceSafe and Rational ClearCase integration
* Archive file support using 7-Zip
* Plugin support
* Localizable interface via resource DLL
* Online manual and installed HTML Help manual
http://winmerge.org/
Espero que te valga...
Un saludo