AgileSCM is an application lifecycle management solution for Subversion, Git, and Mercurial. It allows you to spend more time developing and less time fighting development tools or tied up with administration. AgileSCM is a user friendly, browser-based interface which abstracts developers from the complications of SVN, Mercurial, and Git.
CVS, GIT, and Mercurial as well as other well-known version control systems cannot version directories. In other words, you cannot add empty directories. A "workaround" for this issue is to use placeholder files that are placed into empty directories. These placeholder files can then be committed into the repository and will make sure that, upon checkout, the directory tree is entirely reconstructed. The problem with using placeholder files is that you need to create them, and need to delete them if they are not necessary anymore (because sub-directories or real files were added). With big source trees, managing these placeholder files can be cumbersome and error prone. MarkEmptyDirs can manage the creation/deletion of such placeholder files automatically. It creates placeholder files in all empty "leaf" directories. If later on new files or directories are put into such directories, the placeholder files are not necessary anymore, and are removed automatically.
Meld is a visual diff and merge tool. It integrates with most version control systems. The diff viewer lets you edit files in place (diffs update dynamically), and a middle column shows detailed changes and allows merges. The margins show location of changes for easy browsing, and it also features a tabbed interface that allows you to open many diffs at once.
Mercurial HeadQuarter is a Web service for managing Mercurial repositories. It allows the user to define contact names, define project descriptions, set up access (read and write), set which types of archives are allowed, define encoding charsets, hide/unhide projects, set the presentation style, and redirect access and error logs to files.
RhodeCode (formerly hg-app) is a Pylons framework based Mercurial repository browser/management with a built-in push/pull server and full text search. It works on http/https, has built-in permission/authentication (+ldap) features. It's similar to github or bitbucket, but it's supposed to run as a standalone hosted application and it focuses more on restricted access to repositories. It's powered by a VCS library that can handle many various version control systems.
TurnKey Revision Control Appliance is an integrated revision control server combining the best open source version control systems: Subversion, Git, Bazaar, and Mercurial. A Web interface is included for each system, making it easy to browse through the code base, compare revisions, and manage repositories for multiple projects. No configuration is required and security patches are automatically installed. A Web management interface, configuration console, and AJAX Web shell are provided. To minimize footprint the appliance is built from the ground up with the minimum required components. It runs everywhere thanks to multiple build formats, including an installable live CD, a VMDK with OVF support, and an Amazon EC2 AMI.