Apple has been known to allow their oldest Macs to still be compatible with the latest OS -- which keeps people thrilled. BUT with iphone, OS 4 with multitasking is going to require some heavy processing. The original iPhone (EDGE) will not be able to do this. There is a huge speed difference between iPhone 3G and 3GS that I am not sure 3G could do multitasking either. So, is OS 4.0 going to be something relevant to 3GS and iPhone 4 only? Or maybe only for new hardware only-- 3G/3GS is maxed out?