dcraw is an ANSI C program that decodes any raw image from any digital camera 
on any computer running any operating system. It's become a standard tool 
within and without the Open Source world. It's small (about 3000 lines), 
portable (standard C libraries only), free (both "gratis" and "libre"), and 
when used skillfully, produces better-quality output than the tools provided by
the camera vendor. 

WWW: http://www.cybercom.net/~dcoffin/dcraw/