Honestly, the best way is to find somebody on this board that knows the are and can give you suggestions on what to see, what areas to stay in, and where the best places to eat are.
Take this information, plug it into expedia, priceline, and hotwire and see which one gives you the best prices. Also, regularly check into orbitz.com and the others I mentioned as they frequently offer ultra cheap tickets to different places every week or two. It's a hit or miss as to where they fly out of, and in to.
[edit]When I booked my bachelor party to Atlanta, Fausto1 offered invaluable help as to which parts of town I wanted to book a hotel at, how to get around the area, and which bars & clubs to hit. From there, I just went to hotwire.com and hotels.com and booked things. I did things for about half the price what a travel agent could do this way.