Don't know where you are, but on a whim we walked into a typically busy Apple store in the heart of Denver a week ago and walked out with 2 iPhone 4 32GB models. Took all of about twenty minutes, no reservations since the stores aren't taking any. That was on a Saturday (no shipments arriving) and late in the afternoon, so those phones had been in stock for more than a day. And they still had more available, according to the employee who helped us.
Apple usually ships well ahead of the dates listed on their site; my own shipped almost two weeks ahead of schedule. But it's worth making some phone calls if you don't want to wait. Our local store was happy to tell me what time of day their shipments usually came in when we were waiting on an iPad, and even suggested that I call after that time each day to see if they had what I wanted in stock yet.