Normally you would need to buy a new Socket 775 CPU in order to be able to use a i915 Grantsdale motherboard, but good old Asus decided to create a i915 motherboard compatible with Socket 478, the Asus P4GD1.
This motherboard uses the i915P chipset, but does not supports all the new features. The P4GD1 has an ICH6 south bridge, PCI Express slots, 4 Serial ATA ports, 1 P-ATA port , support for 8 USB 2.0 ports, ... But it does not support DDR2.
Akiba also writes that the power source connector on the motherboard is the same as the 24 pin type of the LGA775 motherboards.
Source:
Akiba, more info about the specifications
here
