Jogging is the best all-round exercise there is, because it works all your muscles: your neck, back, arms, abs, buttocks, thighs and calves.
Another plus for women is that running works your legs rather than your upper body, so it does tone you in the 'right' places. And if you run on hilly terrain you'll get even buffer calves!
Running also does wonders for your posture: you keep your back straight while your pelvis works, which gives you co-ordinated correct posture. The muscles along your spine and abs also get toned while you run.
Like all endurance sports, when you work on the length of your run rather than the intensity, you build up muscle gradually and sculpt your bod rather than beefing up.