I first came across this http://www.colorschemer.com/schemes/ from theanticraft.com blog ~ it is, though, a program that you pay for, but you can get away with seeing the colour schemes that other folks have been posting. It's quite awesome ~ and it's been a huge help in inspiring me to dye my yarns, among other things.
Plus, this past week in dying my yarns, I've discovered how to make the colour Olive: by mixing orange and green, 3:1. And brown is made by mixing red, green, and a little yellow, approx 4:4:1. (yay!)
Finding a free colour wheel is a bit hard online ~ I'm all about the free, but everyone wants to sell you something. So, the colorschemer site will have to do for now. It's a good start, and awesome inspiration nonetheless.