http://info.wsisiz.edu.pl/~blizinsk/git-bzr.html
A helpful guide to using bzr as a client for subversion repositories. Or branching from subversion and then recommitting to subversion while managing intermediary changes in bazaar. The article also covers cvs in the same depth.
http://www.axosoft.com/
AxoSoft provide a proprietary bug / issue tracking system which they licence in various forms. As a hosted solution, a licenced application, etc.
http://www.cs.helsinki.fi/group/propipe/svn.html
Quick introduction to SVN. Short and simple, covers the *very* basic commands. A handy reference.
http://subversion.tigris.org/
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.
http://svnbook.red-bean.com/
This is the online home of Version Control with Subversion, a free book about Subversion, a new version control system designed to supplant CVS.