AMD has been talking about the AMD Fusion since 2006. The AMD Fusion will have both the CPU and GPU on the same die, but in different cores.
Rumors have been circulating for a while now on the details of the CPU and GPU chip. A new rumor appeared in Asia on HKEPC claiming that the AMD Fusion codename Shift will be featuring a RV710 architecture.
The AMD Fusion would be built with 45nm process by TSMC. The integration of the CPU core and the Kong codenamed RV710 GPU is apparently not complete. The CPU and GPU are on the same chip package though.
More details on the HKEPC (Chinese language).