Is AMD changing their CPU naming scheme again? That's currently a rumor, but the company is said to be readying a new five-digit naming convention for their processors starting with the introduction of their 45nm units. That would include the as of yet unreleased Phenom X3 and Phenom X4 models. The roadmap reveals other information about the processors, including clock speeds and supported memory, though none of it is unexpected cache sizes, clock speeds and TDPs are all what we've already seen from similar CPUs.
It primarily seems that the numbers would not necessarily directly indicate how many cores or how much cache a CPU had.
It was over a year ago when AMD changed their naming scheme away from the traditional Athlon-only moniker and picked the new Phenom title, though that name would still be stuck to the five-digit named CPUs if indeed they do change. There has been no official word from AMD as of yet.