GimpLensfun is a Gimp plugin to correct lens distortion using the LensFun library and database.
New release: 2013-05-04 GimpLensfun v0.2.3
Install to: GIMP 2\lib\gimp\2.0\plug-ins\
Database: Gimp2\share\lensfun\
The new one added 8 more lens.

I think, Tools | GEGL Operations | lens-correct op also uses LensFun.
Hugin, darktable, Rawstudio, digiKam, UFRaw use LensFun.

If your lens is not in the LensFun database, with a little work, you can Adding new lenses to the database.

More info at Libre Graphics World
LensFun library goes back to its roots

Unrelated GEGL operation examples

I didn't know this existed. Even though I'm not a photographer, (I can only point and shoot) I do see how useful this plug-in would be.

I never could get this plugin to work in Windows for me.

Rod, My camera is not listed in the LensFun database so I just use a similar model's settings and it works very well. It helps, but it's not required, to have the EXIF information. It's not for use with XCF files (you'll get errors), use a copy of your original JPG, TIF or RAW.

[EDIT]
If your getting errors try, un-checking, Scale to fit.