Personally, I use Scintilla Text Editor for Win32. You can google for it by that name. But that's not to say it's the best; just what I'm used to.

This question is also discussed in Perl's documentation. And in case you haven't noticed, if you have Perl, you probably have it's online documentation. Have a look at perlfaq3, under the heading, "Is there an IDE or Windows Perl Editor?"

While you're wandering around in the Perl documentation (also known as the POD), Have a look at perlfaq1 under the heading, "What's the difference between 'perl' and 'Perl'?" Therein you'll find a concise discussion of why you should refer to the language as Perl, the implementation (the executable) as 'perl', and why nobody ever uses 'PERL'.

Most of all, dig in and have fun.