The next AMD processor to come is the Athlon 4, which is based on the Athlon.
The Athlon 4 is different in that it
1. Has a thermal diode. Which means the processor will run cooler. This part has been named the Palomino.
2. Enhanced data prefetch (added SSE instructions, I think an extra 52 instructions). Just means it will run software better.
3. Enhanced TLB. Kind of the same as # 2.
It will debut at 1.53 GHz sometime in August/September supposedly.
The nForce chipset (also with enhanced data prefetch) will come out roughly at the same time as Athlon 4.