As everyone knows Stave Jobs has said that multitasking will not be enabled on the iPhone 3G.
Scattered reports are now coming in that the 3G is in fact perfectly capable of multitasking using iPhone 4.0 (backgrounder worked just fin on 3G). The below video demonstrates a jailbroken 3G running the iPhone 4.0 OS with multitasking.
Multitasking is not an official part of the release for 3G but reports are that it can be enabled in settings. It remains to be seen if that will be nerfed in the final release.
So when apple tells us that hardware cannot support multitasking on older devices you have to wonder why. Are they trying to get rid of the older iterations or does the 3G have long term stability issues with multitasking.