BEST ADVICE FOR IPHONE 3G OWNERS...
Return your phone to the Apple or ATT store for immediate replacement.
Since only 2% of iPhone 3Gs are affected, that pretty much narrows this down to a hardware problem like a bad chipset. Even if Apple fixes the problem through software, most likely Apple's software solution is probably going to slow down the phone slightly to compensate for Infineon's bad chipsets and memory that fails to meet spec.
I would not under any circumstances settle for a software quick fix for what is obviously a hardware problem.
By the way, no, I don't have an iPhone 3G, but I do have an iPhone 2.5G and don't have this problem nor would I accept a quick fix software update for such a problem.
My opinion is that Apple should recall the affected phones and probably already knows the affected serial#s already. For a phone this expensive, I think Apple's response is quite poor and I say that as a lifelong Apple fan & Mac user since 1987.