Check out the photography stickies here and on r2r and reefcentral.
There are two effective ways on higher end cameras, 1) adjust white balance on your camera with either a white card or change the cameras preset adjustments however the blue is so intense this method often does not work adequately 2) preferred method: shoot in raw mode and adjust kelvins in programs like photoshop elements or Lightroom.
On point and shoot and camera phones, there are usually whitebalance preset adjustments like cloudy day, etc, and you can play around with those to find a setting that you prefer.
LEDs make photography extremely challenging to capture "real, in the tank" colors. You may need to turn blue LEDs way down or off
Good luck. It's a lot of fun to capture the beauty of your tank in a picture