As far as I'm aware, you'll still be able to pick up VOD channels on the Dbox.
Obviously you'll have to wait until it's rolled out in your area and you'll have to wait until someone orders a film before you'll pick up the data stream! The channels won't be there all the time, only when someone orders one.
No it is a different frequency. As far as I know you will need to do a scan using a dvb-c card. Or get the frequencies from someone in your area. But I wouldn't bother as the likely hood of you tuning into the channel at the same time the person orders the film is very doubtful. So you will probably chatch the end of a movie 3 or 4 times. Anyway search the forum as I started a post concerning this matter a couple of weeks ago.