There are the new DateTime::Format modules, but I don't see a way they can currently be used to dispatch a given date string to the right module. You could keep a list of regexen that each DateTime::Format module matches against and then send the date string to the first module that matches. You'll want to talk to the people on the datetime@perl.org mailing list first, though.

----
I wanted to explore how Perl's closures can be manipulated, and ended up creating an object system by accident.
-- Schemer

Note: All code is untested, unless otherwise stated