Read over the stickys on nutrition and weight training. Read them at least 2x. There is a ton of information and can really help when getting started. Use Fitday.com to keep track of you calorie, protein, carb, and fat intake.

What does your work out routine look like? Your cardio should last around 45min and should be done 2-3 times a week, depending on your goals and body type. One of stickys hits on this and says it takes approximatly 30min before you begin to burn fat.

Hope this helps. I'm fairly new also so the other guys should be able to help with more details.