it'll burn calories and will tone you up. muscle burns calories which is why trainers will tell you to do weight training too.
One sure fire way to drop weight fast, is to cut sugar out of your diet. Not easy, as almost everything contains sugar! But it's the one thing your body really...
Elliptical trainer is in between, and works upper and lower body.
Just bought one off a link that helped fund nsc ;-)
Body Sculpture BE5920 Fan Elliptical Trainer £99 from amazon.