If your like me and have little time to devote to actual hard core study then Drawspace is prefect for learning how to draw or just to polish your current skills. Once you sign up for an account (Its free) you gain access to dozens of detailed PDF formatted lessons that instruct on every topic from what kind of drawing tools to get to a study of facial muscles. Pretty much covers all the main points you need to get the basics of drawing. Go out there, grab a pencil and DRAW!
Drawspace.com – Drawing lessons