Take a look at CGI::Application. It's a simple framework that gives you a basic setup for doing this kind of thing *). CGI::Application::Session might be useful too.

*) It might be too basic for some applications, I wrote my own "replacement" to make it easier to throw/catch exceptions and break out of the flow. If you're not heavily using exceptions, and you're currently using basically one single script, it will probably be good enough.