You don't need to take a class! The best book I know, which is one of those thin craft monograph types, is Teach Yourself to Knit, by Eve Rosen, and you can get it from abe.com:
http://www.abebooks.com/servlet/Sear...o+knit&x=0&y=0
The illustrations and explanations are really clear. I still pull it out to remind myself how to do something I haven't done in a while.