You can read up on color theory but then again it is just a theory isn't it?
I've found that the best way to create a color scheme is to find an image or photo online that you like.
Then you can use an "eyedropper" tool in a paint program to sample colors of different values from the image.
If you'd prefer a less hands on way you can try one of the links listed here...
http://www.hollowcube.com/talk/archives/000506.php
I like this one best...
http://www.pixy.cz/apps/barvy/index-en.html