Someone recently made a comment about the difficulty in mainting duplicate perl and CPAN setups using the CPAN module. (The comment was made in a post to the CGI::Application mailing list.) I don't think this is the case, and so I set off to verify the top of my head answer, which was:
perl -MCPAN -e autobundle
I was composing my reply when Michael Peters more comprehensively answered the question by provinding a link to The CPAN Frequently Asked Questions