This is an excerpt from the ExtUtils::MakeMaker module. MakeMaker is the module used to generate Makefile.PLs for module installations. I prefer putting new modules in site_perl, myself, but if you want to keep your environment homogeneous, you could use the LIB attribute (I also include PREFIX 'cause you might find it useful):

     PREFIX and LIB attribute

       PREFIX and LIB can be used to set several INSTALL*
       attributes in one go. The quickest way to install a module
       in a non-standard place might be

           perl Makefile.PL PREFIX=~

       This will install all files in the module under your home
       directory, with man pages and libraries going into an
       appropriate place (usually ~/man and ~/lib).

       Another way to specify many INSTALL directories with a
       single parameter is LIB.

           perl Makefile.PL LIB=~/lib
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