The OpenRAW Solution
We want camera manufacturers to publicly document their RAW image formats — past, present, and future.

The goal of OpenRAW is to encourage image preservation and give creative choice of how images are processed to the creators of the images. To this end, we advocate open documentation of information about the how the raw data is stored and the camera settings selected by the photographer.

http://www.openraw.org/

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dcraw is an open source computer program which is able to read numerous raw image formats, typically produced by high-end digital cameras. dcraw converts these images into the standard PPM and TIFF image formats. This conversion is sometimes referred to as developing a raw image (by analogy with the process of film development) since it renders raw image sensor data (a "digital negative") into a viewable form.

http://en.wikipedia.org/wiki/Dcraw

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The Unidentified Flying Raw (UFRaw) is a utility to read and manipulate raw images from digital cameras. It can be used on its own or as a Gimp plug-in. It reads raw images using Dave Coffin's raw conversion utility - DCRaw. UFRaw supports color management workflow based on Little CMS, allowing the user to apply ICC color profiles. For Nikon users UFRaw has the advantage that it can read the camera's tone curves. Even if you don't own a Nikon, you can still apply a Nikon curve to your images.

Gimp plugin to decode RAW
http://en.wikipedia.org/wiki/UFRaw

GUI Ports:
Windows
http://www.wizards.de/rawdrop/

MacOSX
http://www.frostyplace.com/dcraw/