How do I create a Lion Partition?

Hey everyone, I have a lot of games and apps that aren't too compatible with lion (yet, they'll probably be updated within the next month or two) and I'm part of the Up to Date program. My question is, how do I create a partition for lion the minute I finish downloading it form the app store? Can I still transfer some of the files on Snow Leopard to Lion even if I create a partition? Thanks