An Apache SVN client, right where you need it most
TortoiseSVN is a Subversion (SVN) client, implemented as a windows shell extension. Which means it's available right where you need it: in the Windows file explorer. It's intuitive and easy to use, since it doesn't require the Subversion command line client to run. Simply the coolest Interface to (Sub)Version Control! NOTE: The project has moved to osdn.net: https://osdn.net/projects/tortoisesvn/
Windows visual diff and merge for files and directories
WinMerge is a Windows tool for visual difference display and merging, for both files and directories. It is highly useful for determining what has changed between file versions, and then merging those changes. WinMerge has Unicode support, Flexible syntax coloring editor, Visual SourceSafe integration, and Windows Shell integration. Regexp filtering for filenames and lines. Side-by-side line difference and highlights differences inside lines. A file map shows the overall file differences in a location pane. The user interface is translated into several languages.
TortoiseHg is a shell extension that let users of Mercurial SCM (Hg) work directly from MS-Windows Explorer. It also includes a command line tool, hgtk, for use on Linux and other platforms.