That is what I meant: if you erased your harddrive for a clean install, you would then have to first install 10.5 from Leopard DVD and then upgrade to 10.6 from Snow Leopard disk. But I'm working from only a cursory reading of blogs/news, so it could be quite different. Or you meant something different by "clean install" than I understood. With Bootcamp / Parallels installed, I'm wary of the wipe and reinstall option: I don't like having to reinstall and reactivate Windows. So I'll do the upgrade option.