Apache::Registry is one of the simplest ways to use mod_perl. It takes a CGI-like script from a CGI-program-like-file, and turns it into a specific subroutine invoked when a particular URL is requested.

It's running at full mod_perl speed, but you'll find for more flexibility, you'll want to get away from the "persistent CGI" model and more towards "content handler" and "web application" models as you progress in your mod_perl knowledge.

-- Randal L. Schwartz, Perl hacker