Weight loss, just like weight gain, begins in the kitchen. cardio is a good start, but this is a battle fought nutritionally. Realistically, most people find that eating around 1800-2000 healthy calories a day works best for safe, gradual weight loss. Log your normal diet for a week and use a site like
www.fitdays.com to find the nutritional value of your meals. Then experiment by eating say, 300 calories less then your normal maintenence level and see how that works.
But thats just the bare basics here. I would recommend talking to a Personal Trainer or reading articles from sites like
www.bodybuilding.com to help you create a realistic diet plan that you can encorporate your exercise into.