If you want to go all-out and install the latest version of Perl along with all your favorite modules, you can compile and install a separate build in /usr/local and not worry about interfering with the one that came with Mac OS X:
rm -f config.sh Policy.sh sh Configure -de make make test make install
By default, Perl installs itself under /usr/local with a directory layout that matches other Unix systems. If you specify a prefix of /usr to Configure ( sh Configure -de -Dprefix=/usr ), it switches to the Mac OS X-style directory layout, putting modules in /System/Library/Perl and /Library/Perl (you can look at the output of perl -V for complete configuration details).
Using a prefix of /usr on a production system is not recommended, since it will probably interfere with the operating system's idea of where Perl should be and how it should behave.