The best way to restore the colors is to use a strobe.  ;->

Elements will do this very nicely. Here is my typical process:

1: Burn a CD of my original images straight from my memory card.
2: Copy the images from the memory card to my computer's disk drive
3: Open the image in Elements and use the controls in this order:
 a. Auto Contrast
 b. Auto Levels -or- Auto Color Correct
4: Save the image

I have found that Photoshop's Interpretation of "Auto Contrast" often
works better than using the Auto Levels for underwater photos. Usually
Auto Contrast is all the color correction I want done.

Manually adjusting the "Levels" setting _sometimes_ works better than
using the "Auto Levels" function. Select the "Levels..." menu item and
slide the outermost arrows to the point where the histogram data begins
for both the light and dark side of the image.

Good luck!

Dan

You can't restore what isn't there.  If you use a strobe, the color
information will be there and you can use color correction to bring the
colors out.