[Typo3] New site in the wings help..

[SlickPrinting]

One of my sites has been online now for almost three years(a three your old version of postnuke). After installing TYPO3 in a sub-folder and playing with it for a few days, my mind was made up. I want to dump my old postnuke site and re-create it with TYPO3. Of course I need to create the new site and have it ready before dumping the original. My question is this, If I develop this new site in the TYPO3 subfolder, can I (when ready) load the new site to my root? And if so, what is the procedure?
I hope I didn't miss this in a docs. somewhere......