Saw WWDC 2007 keynote and tried installing Safari 3 Beta on my Macbook (Mac OS X 10.4.9) only to see that it behaves rather weird,it doesn't show up, after deleting and trying to reinstall Safari 3 Beta, all I get is "You cannot install Safari 3 Beta on this volume. This volume does not meet the requirements for this update."

I dint' give up,searched for solutions online and found none :( Then tried installing the Safari3BetaUninstall.pkg without even installing the Safari3Beta.pkg!! It asked for a restart and voila, I see Safari loading to its full glory!! Enjoy Safari and all the new features!!