First of all, for some of you, please know what you're talking about before making blanket statements like "Flash doesn't do 3D."
I make my living making 3D things in flash, like augmented reality. Here's my suggestion:
Use Papervision3D, since the internal, simple 3D in Flash CS4 is based on it, and because its totally free to use for commercial projects. Using a different, proprietary engine, then adding in-game advertising could land you in court, unless you want to pay the several thousand dollar licensing fee.
Second download the free Flex SDK, learn it, and make the program with your favorite text editor and the command prompt. The Flash IDE was originally created for keyframe animations and doesn't translate well to traditional software development, which is best for 3D work in ActionScript or any other language.
@blubfaceproduction, when you look at this, it will be extremely daunting at first. Have heart, take the time to learn it, and find yourself able to do more than 99% of the people on these forums. Everything else you do in ActionScript after this project will be easy.
Papervision3D
Flex SDK