I've written a Makefile for Linux/Unix users. I don't use Windows or Macs so can't vouch for its use there, though if you set GIMP2_DIRECTORY on either it should probably work.

Makefile is attached.

I did a simple script to install gps, as I can see yours is a little more complex than main, I am going to post my script if someone is interested

script is attached

As you can see is my first script ever :)

Is anyone going to do a graphical installer in which you can select what you want to install explaining what does everything?, and then a .deb for install in Ubuntu. I have no idea of how to do that, but if no one do I'll try out

A graphical installer doesn't seem necessary, AFAIK. An RPM would be pretty easy to do. I might do that for Fedora. That could be run through alien to produce a .deb. I haven't made manual .debs in a long time and don't really remember how to do it (just remember not liking the format).

But the problem is relocation on multiple distributions. Not every distro places the GIMP package in the same parent directory. Not sure the right way to deal with that problem, though the Makefile could probably deal with it (sed scripting the spec file).

Of course, RPMs and .debs are of no value to Windows and Mac users. Can't help there since I don't use either.

I'm using Gimp 2.6.6 on Vista. All I had to do was directly un7zip the archive to "C:\Users\your_username_here.gimp-2.6" and it worked. Not sure about the all users directory, though. Thanks for taking this initiative!