Perl programs are just plain text, so any editor will do.
If you're on Unix, you already have an IDE--Unix itself. The UNIX philosophy is the philosophy of several small tools that each do one thing and do it well. It's like a carpenter's toolbox.
If you want an IDE, check the following: Komodo
ActiveState's cross-platform (as of April 2001 Windows and Linux), multi-language IDE has Perl support, including a regular expression debugger and remote debugging ( http://www.ActiveState.com/Products/Komodo/index.html ). (Visual Perl, a Visual Studio.NET plug-in is currently (early 2001) in beta ( http://www.ActiveState.com/Products/VisualPerl/index.html )).