To add to what both mbethke and Tanktalus have already said, Perl can be pretty fast with just single CPU linear processes. I was doing some stuff for fun where I extracted all the music related entries from the Wikipedia dump files (about 8 GB compressed) using a pull parser out of CPAN and it was slurping them all out and dumping to a file in a couple hours on a 1.8 GHz Macbook Pro 1,1 (not even a Core Duo) with 2 GB of RAM. And I could do other stuff at the same time.
So unless you're doing something like sorting through CERN data to check for the Higgs yourself, or something that requires a lot of real time processing on a bunch of data, working to split a task to multiple cores might be overkill. Unless it's for entertainment, and then you should post it as a CUFP when it's working.