Free Version Control Tools
Mercurial is a free, distributed source control management tool. Mercurial is written in Python and is available on Microsoft Windows, GNU/Linux, Mac OS X, Solaris 11 Express and others.
Darcs is a free and open source, cross-platform version control system, like git, mercurial or subversion but with a very different approach. Thanks to its focus on changes rather than snapshots, Darcs can offer a freer way of working, and a simpler user interface.
monotone is a free distributed version control system that runs on linux, solaris, OSX, windows, and other unixes, and is licensed under the GNU GPL.
TortoiseCVS is version control software released under the GPL that integrates with the Windows Explorer shell and lets you work directly by right-clicking files and folders. Overlays on top of the normal icons show you the state of files.
JEDI Version Control System
The object of the JEDI VCS project is to create an open source VCS system based on the existing FreeVCS. This will allow current FreeVCS users to migrate to JEDI VCS, while continuing to use the existing server portion. The first release candidates are available for download.
This is the Wiki for Arch Revision Control Systems such as GNU Arch. The Wiki pages include links to a short tutorial and downloadable binaries and source and installation instructions.
The goal of the Subversion project is to build a version control system that is a compelling replacement for CVS in the open source community. The software is released under an Apache/BSD-style open source license. Suports various flavours of Linux, Windows, OsX and IBM platforms.
CVS is the Concurrent Versions System, the dominant open-source network-transparent version control system. Its client-server access method lets developers access the latest code from anywhere there's an Internet connection. Client tools are available on most platforms.
SourceJammer is a source control and versioning system written in Java. It consists of a server-side component that maintains the files and version history, and handles check-in, check-out, etc. and other commands; and a client-side component that makes requests of the server and manages the files on the client-side file system. SourceJammer is coded in 100% Java, so it is platform independent.