ViewVC is a browser interface for CVS and Subversion version control repositories.
By Mike Pilato, Brian Fitzpatrick, and Ben Collins-Sussman.
These points are taken directly from the Subversion project web site.
Subversion is meant to be a better CVS, so it has most of CVS's features. Generally, Subversion's interface to a particular feature is similar to CVS's, except where there's a compelling reason to do otherwise.
Lack of these features is one of the most common complaints against CVS. Subversion versions not only file contents and file existence, but also directories, copies, and renames. It also allows arbitrary metadata ("properties") to be versioned along with any file or directory, and provides a mechanism for versioning the `execute' permission flag on files.
Trac is a web application which provides issue tracking, timelines and Wiki with Subversion integration. Trac is written in Python and can be either run as a cgi program (any web server) or within mod_python (Apache).
vss2svn is a Perl script which converts Microsoft Visual SourceSafe (VSS) repositories to Subversion.
SVK is a decentralized version control system written in Perl which uses the Subversion filesystem.
TortoiseSVN is a Windows shell extension which adds Subversion information and commands to Windows Explorer.
TortoiseSVN is Subversion for most Windows users. TortoiseSVN brings the full functionality of Subversion into the Windows shell.
There are also some very useful extras. Most notable is the "Repo-Browser" which enables queries and changes to be made directly on the repository.