Last post outlined a framework for a general dynamic warm-up that, if you follow it, will give you a pretty decent bang-for-your-buck. If you perform a dynamic warm-up before you lifting sessions, you'll be ahead of the game and prepared to slam some weights around. However, we can tweak your warm-up to make it more specific to the Big 3 (squat, bench, and deadlift).
Re-inventing the wheel is inefficient, and I loathe inefficiency, and so is re-writing a blog post. I wrote a piece for Breaking Muscle last year about how to warm-up for the Big 3 and you can read that HERE.