Subversion (SVN)

Subversion is the most widely used version control system in the Ruby on Rails world. It is an open-source project itself, and is used by many open source projects.

CollabNet provides commercial support and training for the open-source Subversion version control system. You can download the software from their site for free.

The official book about Subversion, available free online. You can also buy it as a printed book.

Hosted service for Subversion and bug/issue tracking. Free plans for single developers, paid plans for multiple developers and multiple projects.

Commercial Subversion hosting.