I find a lot online that is really cool for us artists. I know you guys might find some stuff and places to share too. So, lets share some stuff.
I found this today http://colorschemedesigner.com/
and it is useful. Kinda cheating a bit since in school we are taught to have the color wheel and the combinations in our head, but if I'm blocked on a color scheme. I used to make a grid of a color scheme in Ps manually, but this is good if I need to be quick.