Download from CPAN/wsnyder.
SVN::S4 runs on any operating system with Perl and Subversion, though it has only been tested on Linux.
If you're using a recent version of Perl, just:
cpan install SVN::S4
Otherwise, untar, make, test, and install manually: cd SVN-S4* perl Makefile.PL make make test make install
tar xvzf SVN-S4*.t*gz
After installation, see the kit's README.
See the Veripool Perl Module FAQ for common installation problems.