Here is a nice general article on Weight management. Weight Management

One misconception that some people have is that you have to exercise for 30 minute to an hour in order to get the benefits. This is not always the case. You can get similar weight loss benefits from doing several shorter duration workouts throughout the day. This may not be the best way to get the cardio-benefits but I will still use up calories. For untrained individuals 10 minutes can be enough to get the some cardio- benefits as well.

In reality the bottom line in weight loss is to expend more calories than you take in. Unfortunately consistently doing it on a daily basis isn't easy.