From what i understand (which aint much) the 4x4 CPU/GPU combo is coming out next year...
I don't know if it will support AM2, let's pray that it does...
#1: Amd is coming out with the K8L setup that is supposed to increase performance however we don't know how much and they are shrinking the die down to 65nm by the end of the year and after that just small improvements from there nothing big that I can remember form the road maps and they have the 4x4 so by the end of the year the gap should close a bit but not by much unless AMD is hiding something
#2: So far it looks that way for the Dualcore but the 4x4 will be a different set up. But so far the AM2 socket looks good for a while now. However there are going to be over all improvements on the whole set up so if you want all that you can get out of the AM2 socket you might have to upgrade the motherboard