How to replace Leopard with Snow leopard?

[dustintinsley]

I am currently running Leopard 10.5.8. I am going to install SL and by all the guides, I see it is best to install to a new HD. As I only have 1 internal HD, I plan on installing to and external HD, if possible. What I would like to do at that point is install SL onto my internal HD, preferably formatting that drive and starting clean. How do I go about this? Since I only have the 1 internal drive, I'd rather just run SL instead of dual booting between 10.5.8 and SL...