If you can't find it with 5 seconds of google/search.cpan.org, it doesn't exist

• OAuth::Lite2::Client::Agent
• OAuth::Lite::Agent
• Net::OAuth2
• LWP::Authen::OAuth
• WWW::Mechanize
• https://developer.foursquare.com/docs/
• https://developer.foursquare.com/docs/oauth.html
• https://developer.foursquare.com/docs/index_docs.html
• How to checkin to foursquare via backend using PERL and PHP
• Gaming foursquare with 9 lines of Perl
• Gaming Foursquare in Two Lines of Perl