If you're wondering about the outs you have to catch runner-runner, and how that figures into pot odds, best thing to do is add 1/2 an out to your calculations.

So if you have AKs, and the flop comes Q72r with 1 spade, figure you have 7 or so outs. 3 aces, 3 kings, runner-runner spade flush, and runner-runner broadway.