iPhone 3G upgraded to iOS 4, does it now support multitasking?

Can anybody clarify the availability of multitasking on an iPhone 3G?

I went through several documents in Apple's HI guidelines, which state that:

Multitasking is available on certain devices running ios4 and later.

What does it actually mean? I have an iPhone 3G which doesn't support multitasking, so now if I upgrade my iPhone 3G to iOS4 or later, will it support multitasking?

Only iPhone 3GS and later support multitasking. iPhone 3G does not, regardless of which version of iOS is installed, unless you jailbreak it.

The processor has nothing to do with multitasking capability.

It's a software feature that you can enable by jailbreaking the iPhone.