Anything that gets your heart rate up will help you to lose weight. Your body loses weight all over and you cannot tell it to lose one form of weight over another. You will lose fat, you will also lose muscle and glycogen (carb stores).
The best form of cardio for weight loss seems to be interval training- or if your really good, High Impact Interval Training which is interval training but with that much more energy ploughed into it!
Interval training can be done on most machines or in most workouts, what your looking for is 40 seconds-2 mins of going at something as hard as you can, say sprinting or similar, getting your heart rate as high as you can, followed by the same amount of time to slow down, get your breath back and repeat. You do this 6-8 times per exercise and then move onto something else. It works better then straight forward cardio where everything is even as it tests your fitness and constantly changing things so your body doesn't get used to them costs your body more calories then otherwise.
There are some stickies on HIIT which explain it better then I can.