WinMerge - Open Source visual text file differencing and merging tool

WinMerge is an Open Source visual text file differencing and merging tool for Win32 platforms. 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 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