Preorder saves you 20%, you go to the official photopass site and order (and pay with your disney credit card of course) and it is $99 (I think, it was last year) for the CD of every pic you get on photopass while you are there.
Photopass share is on the budget board of these threads. It is like the fridge swap.... One person buys the photopass, and you all enter your pics under their name, splitting with four or so families means you only pay 20....but you have to remember that you will have four families pics along with yours on the CD. You print the pics at
Walmart or wherever for ten cents a print or whatever,that is the big savings over buying prints at the park.