This is discussed in two places: first, see A Guide to Installing Modules. Second, read this, section 5 from the FAQ for the CPAN modules:

       5)  I am not root, how can I install a module in a per­
           sonal directory?

           You will most probably like something like this:

             o conf makepl_arg "LIB=~/myperl/lib \
                               INSTALLMAN1DIR=~/myperl/man/man1 \
                               INSTALLMAN3DIR=~/myperl/man/man3"
             install Sybase::Sybperl

           You can make this setting permanent like all "o conf"
           settings with "o conf commit".

           You will have to add ~/myperl/man to the MANPATH envi­
           ronment variable and also tell your perl programs to
           look into ~/myperl/lib, e.g. by including

             use lib "$ENV{HOME}/myperl/lib";

           or setting the PERL5LIB environment variable.

           Another thing you should bear in mind is that the
           UNINST parameter should never be set if you are not
           root.
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