Perl comes bundled with OS X, I just don't know what that "example program in the perl folder" you're talking about is. Where is it located? Did you install something? Like MacPerl as the previous poster suggested.

You shouldn't have to install anything at all to write Perl scripts. To use them, you'll have to go with the Terminal.app located in /Applications/Utilities. If you want to create double-clickable program with an OS X GUI, you could use something like Pashua.