And last, but not least, get a copy of Mike Senior's book Mixing Secrets For The Small Studio. The book is great and he has a website dedicated to the book that contains a wealth of resources including "More than 150 free multitrack projects in a variety of different musical styles, for use as mixing practice or as a basis for educational assignments." and "More than 350 audio demonstrations to illustrate important points in each chapter of the text."

http://www.cambridge-mt.com/ms-intro.htm