How do I acquire a lean stomach showing a nice six pack?

Ok. Let me rephrase that. I know eating is important and exercising is also important. All that aside, if you need a boost to get some fat out, what would one recommend? I have been working out for a while and realllly watching my diet and staying away from "bad" food. I do sit ups, crunches, etc. But the fat in my stomach area will not go away. Underneath the fat, I am strong and the muscle is tightened, but the fat remains. I am not over weight but over the years I aculated fat only in my stomach. Any suggestions?