So you've spent all your hard earned cash on a camera that shoots RAW images. You need to do your magic now. Then you realize... you need Photoshop. Plus some plugin to open that RAW file. But you need money to buy the stuff.
So, now what do you do?
First thing everyone will tell you is, "Try GIMP!" GIMP is short for the GNU Image Manipulation Program. It's free (as in free beer). But alone, GIMP won't be able to open your RAW files.
Enter UFRaw. This other free program can be used by itself or as a plugin to GIMP. 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. Check out this page to see what cameras are supported in UFRaw:
http://ufraw.sourceforge.net/Cameras.html