emacs has cperl-mode, courtesy the unstoppable Ilya Zakharevich (you can get it from his CPAN directory). It can handle syntax colouring, too. M-x font-lock-mode is what does it, I believe. I've never paid too much attention to the intimate nasties of Emacs' colouring and font fiddles.

There's PerlBuilder, but my experience with it was not encouraging. David Grove, known primarily for paranoid anti-Microsoft anti-Activestate rants, has released a commercial Perl IDE called Code Magic. I haven't seen it, so can't say how good it is.