I'm an endomorph, so I pretty much have to do cardio every single day. It's better to divide up the cardio and weight training so that you don't over train and raise your cortisol levels, ideally, but most people don't have time to go to the gym multiple times a day.
I normally do about 30 - 60 minutes of cardio during the morning, and then I'll do my workouts in the evening for an hour to an hour and a half. If I can't separate my cardio from my workout, then I'll do my hour and a half workout first followed by 30 minutes of cardio.
I personally don't like doing cardio before my weight training because you burn a lot of energy that could be used for lifting weight. Use that energy wisely to build muscle and then you turn your body into a fat-burning machine. If you do too much cardio, then you'll burn more muscle, making yourself actually fatter in the long run. Focus on building muscle, and the fat loss will come as a result. You'll look better and have a lower body fat to muscle ratio, which is what you want.
Some argue that doing cardio after you workout is the best because you depleted your glycogen stores during your workout, so now your body has to tap into your stored fat in order to get energy for your cardio. Some agree with this hypothesis, while others do not. I tend to agree with this training method, and I have been doing it for quite awhile now. I've never like doing cardio before my workouts, and I typically never recommend others to do it either.