The various base URLs look like:
Common SVN commands
svn co https://svn.sourceforge.net/svnroot/cashutil/trunk cashutil
The online manual "Version Control with Subversion" is a very good resource for information about subversion.
See, Chapter 3. Guided Tour and Appendix A. Subversion for CVS Users.
The command-line client "svn" has an integrated help system; "svn help" which will provide the top-level command list, and "svn help <command>" which provides detailed help for a specific command.
How do I get developer access?
Submit patches to the QOF-devel mailing list (as attachments, compressed if appropriate). If these work out, you can be considered for developer access.