Both have 2 PCI-x slots and will let you run 2 video cards but they will not let you SLI them. But you could run both with monitors attachd to both giving you multiple displays.
If you want SLI you need a motherboard with an nforce 4 SLi chipset. No Intel based chipset will suport any kind of SLi.
Unfortunatly i can't find any nforce 4 SLI chipset boards that support a C2D on Newegg. Maybe one will be able to support C2D with a bios update. Not sure though. From what i've read it's better to run a C2D with an intel chipset. I've read about problems between the nforce4 shipset and C2D's.
I don't understand how come they don't let me sli? SLI is supposed to connect 2 PCIe SLI GPU