http://www.macworld.com/2005/03/secrets/maygeekfactor/index.php?pf=1 shows that dual booting versions is possible... Easier OS Upgrades When installing a new version of OS X, do so on a second partition. This is useful when youre not sure you want the update, as well as when you want an easy way to copy your Home folders contents after a clean install. But I was wondering if theres a log in boot to partion selection screen or if you have to say press f8 or something to manually select the partition that you would like to boot to. Just fully preparing for 10.5 and i want all the tutorials i can get my hands on at this point.