is a translator library for raster geospatial data formats that is released under an X/MIT style Open Source license by the Open Source Geospatial Foundation. As a library, it presents a single abstract data model to the calling application for all supported formats. It also comes with a variety of useful commandline utilities for data translation and processing. The NEWS page describes the July 2011 GDAL/OGR 1.9.0 release.
The related OGR library (which lives within the GDAL source tree) provides a similar capability for simple features vector data.
Master: http://www.gdal.org
Download: ftp at remotesensing.org, http at download.osgeo.org
The gdal-dev@lists.osgeo.org mailing list can be used for discussion of development and user issues related to GDAL and related technologies. Subscriptions can be done, and archives reviewed on the web. The mailing list is also available in read-only format by NNTP at news://news.gmane.org/gmane.comp.gis.gdal.devel and by HTTP at http://news.gmane.org/gmane.comp.gis.gdal.devel. Archives since 2005 are searchable on Nabble.
Some GDAL/OGR users and developers can also often be found in the gdal IRC channel on irc.freenode.net.