The Basic Crazy Quilt Course and Intermediate Crazy Quilt Course include more information on Color Theory and Mixing Colors. But, here is a quick reference for you to put into your purse.
The above photo is a printable version of a standard twelve-part color wheel...and includes the most recognized Color Schemes commonly used. This is a handy pocket reference...just print and cut apart.
It's pretty clearly understood just by reading the captions...but if you want more color theory discussion...please sign up for the BCQC and then the ICQC-101 Modules.