I cant say this enough. While running does help SOME, squats are the way to go if you want to diminish your cellulite because you must build lean muscle to take the place of those fat deposits that sit beneath your skin! They have reduced the whole overall appearance of not just cellulite but the shape of my booty and my thighs. Squats are certainly the fastest way to lift your derrière and help you to look and feel sexier on you'd clothes (and out!).
Start of using a weight that feels comfortable to you and do 3 sets of 12 repetitions. For my squats, I like to use the leg press machine in the gym. Do whatever suits you!