If you do a lot of jewelry photography and have Photoshop, you may be interested in my latest Photoshop tip, Removing a Color Cast, at my sister site, EspressoGraphics.com.
When it comes to photographing my beadwork, I often end up with an annoying color cast even when I photograph the jewelry using a light box, turn off the flash, use an Ott-Lite for lighting and fiddle with the settings on my digital camera. I have found that the quickest and easiest way to get rid of that color cast is to convert the image to Lab mode in Photoshop and tinker with it there.
This Photoshop CS3 tip shows you how to go from this:
to this: