The CPAN-API project (MetaCPAN) aims to provide a free, open web service which provides metadata for CPAN modules.
MetaCPAN is based on ElasticSearch, so it provides a RESTful interface as well as the option to create complex queries. The wiki provides a good starting point for REST access to MetaCPAN.
MetaCPAN allows authors to add custom metadata about themselves to the index. You are encouraged to add your own custom fields. Have a look at this short article on how to expand your author info.
See the installation page in the wiki to start playing with your own MetaCPAN installation.
This project currently has very few committers. If you'd like to get involved, please join our mailing list (see below) and let us know what you'd like to start working on.
http://search.metacpan.org is a pure JavaScript CPAN search engine, which is built on top of MetaCPAN.
You can find us at #metacpan on irc.perl.org
IRC logs can be found here: http://irclog.perlgeek.de/metacpan/today (Thanks to Moritz Lenz for making this service available)
Our mailing list is open to all: http://groups.google.com/group/cpan-api