Hmm, I can't believe no one has replied to this. There's a points calculator here: Velocity> Points Calculator - Reward Flights
But what it will do is quote you a range of points. Basically the points work like money you can buy flights with, so if there's a Virgin Blue sale on then the number of points you need to buy an available sale seat is less than if you're paying the full fare (unlike QFF where there may be seperate 'points' sales, but usually you always require the same number of points to fly the same distance).
The points quoted will start at the number needed for a Blue Saver seat and the top number is for the Corporate Plus fare(I think, might be fully flexible). Of course, how many points you'll require will depend on the Blue Saver rate for that particular flight and if there are Blue Saver seats (or Sale seats) available.
To give you an idea, PER-SYD will cost $229 or 16500 points. You do need to pay a $39 tax and fees on top of the points though.
The program is totally free to sign up to, so even if you only plan on flying DJ the once, you may as well sign up, get the points and who knows? you might fly on them again in the next three years before your account expires.