There are tons of really good color pickers online that will help you find colors for your designs.
Some help you by suggesting complimentary colors, complete color schemes, shades of colors etc.
I think the kuler picker is a pretty good one for all of these.
There’s even a color picker that makes a color scheme based on your IP address.
But I just came across a picker that is insanely intuitive to use.
I won’t even explain how to use it, just give it a try.