If you are looking to see if a particular Perl module is installed on your DreamHost server, you can do so by logging into your shell account, and then enter the following (replacing “Some::Module” with the name of the module you are searching for):

perl -M Some::Module -e0

If you want to know all of the Perl modules installed on your server, or need more detailed info such as versions and documentation then you should check out perldiver - a free cgi script.

And yes, you can even install your own perl modules in your home directory via CPAN.

You can check the wiki for more info and a list of modules installed on DreamHost servers.