There are tons of good guides on the Delaware and I think that you'll find, at least for your first few trips us there, that getting a guide will really enhance your enjoyment. Best of luck!
If your looking for a guide on the Upper D, I would like to recommend my Dad @ Rivers Edge Fly Fishing. He fishes out of a 16' Clackacraft Drift Boat and always puts his clients on fish. Also very affordable rates and a good time. PM me if you would like any more info.