It depends what kind of stretching you're talking about. Dynamic stretching before a workout is recommended, where
static stretching is for afterwards. Static stretching before a workout is a big no no.
However I don't do either around my workouts, but do a lot for my
martial arts. Funnily enough, Martial arts don't seem to have cottoned on to these methods and it annoys the hell out of me when they make me do isometrics before the class because it goes against everything I've learned on the subject. It's weird, they make us do dynamics for the upper body, and the minute it gets to the legs, they switch do isometrics, go figure :S
Dynamic Stretching and Isometric stretching are the keywords you're looking for anyway.