This is basically the same script as in the perl version (and the only functional addition is the choice to use hard/soft light, which is just a minor addition, because you can always tweak the resulting layer anyway).

I made the Python version because apparently GIMP on Windows can't do Perl and OS X and Ubuntu versions only ship with Python by default. After the first release, the entire source code has now been completely purged of all unnecessary, if already censored, swearing; if you are still interested of my thoughts regarding my first exposure to Python-Fu, please read the relevant blog post

Photo in preview © wwwwolf 2008.

Current version: 1.0.1, released 2008-07-04. If you downloaded the first release, you don't need to bother with this update; this just cleans up the code. No bugs are fixed, etc etc. It does clean up the function name and adds a return value, which may help if you want to use this in other scripts or in the GIMP batch mode.

Requirements: GIMP with Python support enabled (you should see "Python-Fu" in the "Xtns" menu).
Has been tested in GIMP 2.4.x, in Ubuntu Linux (the stock GIMP install) and OS X (DarwinGIMP). Should work in Windows GIMP with some prayers and/or general tweaking, but I don't have any special instructions, regrettably.

Installation: First choose install location. You need to figure out where the GIMP keeps its user data (In Linux, for example, it's ~/.gimp-2.4/; I have no idea where other OSes keep the stuff, for example, OS X DarwinGIMP dist probably has changed the location from the usual *nix GIMP location). You may alternatively stick this thing in the system-wide location (/usr/lib/gimp/2.0/ in Linux, in OS X you may browse in the Gimp.app by choosing "show package contents" and look in the Resources folder). Either way, you should locate a folder called "plug-ins" under this folder. Stick the bloom.py file there. You may need to make it executable in Linux (chmod +x bloom.py).