It does work fine on the Release Preview of Windows 8 so I asume it's the same for the final.
Except for that Metro-tile-stuff of course as that is not supported, so DBP and anything done with it will run in Desktop mode (opens the Desktop automatically when launched from the new UI).
You will probably have to install the latest DX9 update as - strange enough - the Release Preview did not have that preinstalled.
So from a DBP programmers point of view your stuff should work the same on any Win 8 as it did on Win 7 and Vista. That includes that you need to work with the UAC limitations of course. This means that you might not be able to manipulate files in your games directory or do anything in the registry as long as the user doesn't launch your program with administrator rights.