There have been many complaints about the performance of iOS 4.0.x on the older iPhone 3G model, in that the two-year-old model, while supported on iOS 4, runs horribly on the new OS. While Apple has acknowledged the issue, and begun actively investigating it, there hasn't been much real news about a release to fix the issue, until now.
The response from Apple CEO Steve Jobs (it's well known that Jobs will occasionally directly answer end user emails), came as a result of the following email:
I've waited patiently through 4.0.1 and 4.0.2, looking for a fix that will make my phone work again. I've read the forums that advise me to jailbreak my phone or use some other method so I can downgrade back to a version of iPhone 3, however I'm not prepared to use a method that is not supported by Apple.
Indeed, you can't downgrade your ROM without jumping through non-Apple approved hoops. Here's what Steve Jobs said in his normal terse manner:
Software update coming soon.
Sent from my iPhone
Soon could mean anything, but it's been noted already that beta versions of the upcoming 4.1 ROM update show improvement in the performance of iOS 4 on the 3G. Apple has disabled several features in iOS 4 on the 3G, including multitasking, due to constraints with regards to the "power" of the older device's HW.
Much as with "Antennagate," videos around this issue have arisen on YouTube. Check out this YouTube parody of iOS 4 on an iPhone 3G.