Geographic Resources Analysis Support System (GRASS) is a GIS software application under a GNU GPL license originally developed by the US Government.
Official GRASS Site
Headquarters site of GRASS. Find download sites, and supporting documentation about GRASS.
Wiki in support of GRASS. Find information about GRASS or contribute your own knowledge about this open source software.
FreeGIS CD for GNU/Linux. This CD contains GRASS, a GIS software application as well as server software for web-based, interactive mapping and programming libraries to enhance GIS development.
GRASS Developer’s Forum
Email-based discussion list for developers that improve and contribute source code.
GRASS How To
Guide to GRASS written in 1997 by David A. Hastings of NOAA.