For any brides who have no idea what colors to pick, or who have one color want another 1 or two but don't know what color(s) to pair with it. It's actually a really useful tool. I use them a lot if I'm painting something or knitting and don't really know what colors I want to put together. How they work is you upload an image and it generates a palette for you from that image. I usually find an image online whose color(s) appeal to me, and use that because chances are I'll like the palette generated from it. I recommend home or interior design websites especially the websites of magazines for this. People generally gravitate towards certain colors sometimes without really knowing it so if you go to Martha Stewart's website or Home and Gardens or wherever and you like the colors of a room you'll probably like them for your wedding.
http://www.pictaculous.com/
http://www.cssdrive.com/imagepalette/index.php
http://bighugelabs.com/colors.php
Images are in same order as links hopefully