Best fix I found using Photoshop.. For people with no strobes

[edrobmaui]

If you already have Aperture 2, then you have a much better option for white balancing your UW pics -- it's called the "white balance" function. You simply check the tool and pick a pixel that's white or neutral gray. See if you like the results. If not, undo and then try again with a different pixel. Super-easy.
Aperture is often used by people shooting in RAW format, but the White Balance functionality still works quite well on JPEGs.

I really like Aperture 2. It's a great option for photographers who work on the Mac OS.

Hope this helps...

Bubbletrubble has hit on the simple solution for color correction by working with white balance. However working with a JPG file is somewhat after the fact since much of the original color information has been compressed. If you have the option to shoot in RAW you will have a wider range of white balance correction with better results.

BTW if you are on a PC Adobe Lightroom will edit WB in JPG as well as RAW format and works similar to Aperture on a MAC.
Ed