Are there any free Perl IDEs out there for Windows that have debugging capabilities, syntax highlighting, and possibly even IntelliSense?
This isn't free but you could have a look at Komodo (ActiveState). When I looked at it a few years ago they were offering a free license for open source developers.
There is an overview of Perl IDE's here. I find Padre very promising, but I'm not sure it already has all features you need (if not it probably will soon).
Padre: http://padre.perlide.org/
GNU/Emacs with cperl-mode: http://gnu.org/software/emacs
Emacs has better editing capabilities (and hilights Perl better, ironically), but Padre might be enough for you.
I forgot to mention that I only program on Windows XP to 2008 Server.
I use enginsite Perl Editor lite version, mainly for the function, variable breakdown feature and the compile/run feature.
if you want more feature then you might want to look at the full version.
Komodo Edit from ActiveState supports debugging and it's cross-platform.