IMHO there is no IDE for Fhem as such. It has fairly moderate requirements for its environment.
I recommend getting FHEM via
SVN on your local machine. I am using
Versions as a GUI on my Mac (quite nasty but AFAIK there does not seem to be any alternative).
For Windows, I believe a combination of
TortoiseSVN and
PuTTY is the way to go.
Second, install one (or even many) Perl versions using
Perlbrew (I believe for Windows you would want to have a deeper look to
berrybrew). It will help you to test using different Perl versions.
You might also want to install cpanm for easy Perl module installation (also see
here).
Personally, I prefer the
TextMate2 editor on my Mac. However, for multi-platform I believe you might want to go for
Atom.
TextMate has direct support for
perl-tidy to clean-up and structure your code which I find to be very useful and convenient. For Atom, there seems to be a
package for integration as well.
Hope this helps to get started.
Regards,
Julian