FWTools GIS Toolkit is a freely available open source toolkit for Windows and Linux that can do more than GIS tricks.
It is a precompiled bundle of Open Source GIS tools.
The FW comes from the initials of Frank Warmerdam,
the originator of the toolkit and current President of the Open Source Geospatial Foundation (OSGEO).
This is a library which historically has been developed and maintained by Frank Warmerdam, but has started to garner quite a few developers.
GDAL is X/MIT licensed (similar to BSD license), therefore the licensing is very generous for commercial use. The toolkit can be downloaded from