Have a look at Komodo from ActiveState. It's a cross-platform IDE for scripting languages, including Perl, Python, and JavaScript. It's currently in development, but it is definitely usable on Windows.
I actually downloaded this and used it. Not to bad, but its still a little kludgy. Another inconvenience is
that you have to download ActiveState Python as well, to even use it. Hope you have a lot of disk space and
memory, as its going to use a lot of both.