there is a pre-compiled windows version of this well know plugin but was available only from a Japanese webside.
( http://www.geocities.jp/gimproject/gimp2.0.html )
For windows user that don't read Japonize ideograms, and do not know how to compile by source i found useful
mirror here
DOWNLOAD LINK
http://photocomix-resources.deviantart.com/art/Refocus-plugin-windows-OS...
please for source code, versions for other OS, more info and updates refer to the developer page
http://refocus.sourceforge.net/
For some reason the freetype plugin, quite useful to edit text and fonts, was removed from gimp-2.4 , and many miss it Work well with Gimp-2.4 (at least on Windows OS)
The windows users that don't know how to compile by source , may found it here http://photocomix-resources.deviantart.com/art/Lost-Found-Gimp-Freetype-...
ready to be installed
For source code , version for others OS and possible updates please refer to the developer side (www.freetype.org ) i'm just mirroring the windows binary because are hard to find
Shape from shading algorithms have been around for a while. Dr. Mark J. Carlotto describes a simplified version using basic trigonometry (Sculptor's Photoclinometry page in the Pacific-Sierra Research Image Shape from Shading section). In that section, Dr. Carlotto describes the Berthold Klaus Paul Horn algorithm for read more »
PDS/EDR format is the image format used by NASA Planetary Data System and by ESA Planetary Science Archives. PDS images from various space missions are available at http://pds-imaging.jpl.nasa.gov/ and http://www.rssd.esa.int/index.php?project=PSA
With the PDS plug-in you can load images from these missions and others:
A python script that generates a contact sheet or index print containing a configurable number of images. Multiple sheets are generated, the filename can also be included.

To install copy to ~/.gimp?-?/plug-ins/ directory or /usr/lib/gimp2-0/plug-ins/ and make executable with chmod +x contactsheet.py
This updated version works with version 2.4 of The Gimp, tiff support is included.
Extends the functionality of /Export Path by allowing for the specification of attribute values (fill,stroke,etc) by encoding these into the path name.
Export path values as SVG file. Script assumes that the path name is an encoding of SVG attributes. These are encoded using:
_[2 letter code][value]_ where 2 letter code is one of:
- fc => fill color (SVG attribute: fill)
- fo => fill opacity (SVG attribute: fill-opacity)
- nm => name of the path (SVG attribute: id)
- sc => stroke color (SVG attribute: stroke)
- sj => stroke line join (SVG attribute: stroke-linejoin) read more »
Create large and natural textures from a small sample. Based on a 2003 research article. Can also create tileable textures. See homepage :
http://gimp-texturize.sourceforge.net/
Sometimes remembered as "texturizer", but the original name is Texturize.
Writtent by Manu Cornet (http://manucornet.net/) and Jean-Baptiste Rouquier (http://www.rouquier.org/jb).
RAWTex is a save plugin for GIMP 2.2.x, 2.3.x & 2.4.x allowing to create raw textures for the PC, PSP, NDS, PS2 or any other architecture handling chunky or compressed dxtc formats.
It can save raw RGBA (5650, 5551, 4444 or 8888) & indexed (T4, T8) textures (with 5650, 5551, 4444 or 8888 palette modes support) as well as DXTC (DXT1, DXT3, DXT5) compresssed ones, it supports the PSP textures swizzle mode and can generate mipmaps, it also have a color key feature to handle transparency and can convert grayscale pictures into alpha channel only textures.
The Unidentified Flying Raw (UFRaw) is a plug-in to read and manipulate raw images from digital cameras and to load them into the Gimp. UFRaw reads raw images using Dave Coffin's raw conversion utility - DCRaw. UFRaw supports color management workflow based on Little CMS, allowing the user to apply ICC color profiles.
Homepage: http://ufraw.sourceforge.net/
User guide: http://ufraw.sourceforge.net/Guide.html
Installer for MS-Windows: http://ufraw.sourceforge.net/Install.html#MS