Nahrie,
When I started pond building, I did the same thing. Really quickly I discovered that all the Sunset, Better Homes and Gardens, Ortho, type books have good basic info, but IT'S ALL THE SAME!!!! Same illustrations, everything! Good basic 'how to dig the hole' and how to plant out the water plants, but very little on filtration and care of critters. If you read one or two of those, it will give you a list of all the OTHER questions you need answers to, and then I'd start cruising the pond forum right here. Go back a few pages and look for peoples' pond builds threads. There are two sides to most of the arguments, ie rocks on the bottom or not, bottom drains or not, but you will get enough info to make an educated decision for what will work for your setup. Mine is a 600-700 gallon stock tank, above ground. Others have in-ground setups, anywhere from 100 gallons to lake-sized, with everything from a feeder fish or two, to Koi with heads bigger than their owner's hands!
Good luck!
Jen