Nvidia will indeed have an integrated graphic core for its Athlon Nforce 4 supporters. We are not sure about the final name as it's too early for that, but the chipset itself comes under the codename of C51G.
It's paired with a new south bridge codenamed MCP05. This means that if Nvidia wants to bring integrated graphics into Athlon 64 chipset segment it had to make a dual chip design. It will follow a traditional north bridge and south bridge design.
Read the complete story here. (The Inquirer)