As has been said, both on this forum and on many others, spot reduction doesn't happen. Your body will lose fat when you burn more calories than you consume, and in general, you'll lose fat first from wherever you gained it last. For most men, the last fat you lose will come from the belly.
"What type of diet helps get rid of these fats though? I know it's going to be different for everyone, but is there a general rule for losing these fats?"
Answer: any diet in which you sustainably consumer fewer calories than you expend, and still meet your basic nutritional requirements on things like vitamins and minerals. If you're trying to lose weight sustainably, do not attempt to burn more than 500 more calories a day than you consume, or else you're likely to force yourself into starvation mode. 500 calories a day will be a pound of fat per week.
I would also add my personal opinion that an extremely high in protein diet - things like Atkin's - is bad for you in the long run. Too many amino acids in your diet is toxic, and can end up causing substantial damage to your kidneys and/or live as you try to get rid of the excess nitrogen.
"Also, what's a good cardio excercise? How many minutes do I want to be keeping my heart rate up?"
Answer: It depends on what you're trying to do with your cardio. The two main points of cardio in a fitness regimen are to increase your cardiovascular function (resulting in a lower resting pulse, a better conditioned heart, lungs that can withstand exercise better, etc.) and to burn calories (useful in weight/fat loss/management). If you're trying to burn calories, as I would imagine you are from posting on this thread, you'll do best in whatever exercise lets you burn the most calories before you're exhausted. That will probably be something like running or rowing, though some people do better with swimming. If it's for the fitness benefit, then you'll want to mix it up with stairs, biking, jumping rope, step aerobics, etc--give yourself lots of different ways of challenging your body, rather than falling into a rut.
As for how long to keep up the heart rate, it again depends on what you're trying to do. For losing fat, the standard advice is to get yourself to 60-70% your maximal pulse and maintain it for 30-45 minutes, 3 or so days a week. For cardiovascular functioning as a whole, you'll want at least some of your sessions to deal with interval work: short durations (30-60s) of really intense activity, followed by a few minutes of recovery at a much lighter pace, cycled 5-7 times.