You can order the hypertech PPIII from Jegs online. We paid $350 for ours.
Personally, I really like it. It makes a huge difference in throttle response, and seems to pull harder. However, I have no dyno #'s to give you to back up that claim....I just go by seat-of-your-pants sensors.
We've used it 4 times since we've bought it two months ago. I think it's a great investment if you are constantly tweaking your car. If you just throw on a few mods, and leave it be it probably won't be worth it to you, but rather a hard programmed chip would be the way to go.
There is a big difference between buying a programmer, and a burned chip......