To get this working you need a 680i SLI or 780a/780i SLI based motherboard with at least 3 PCI Express x16 slots and a GeForce 8800 Ultra of GeForce 8800 GTX. The upcoming GeForce 8800 GT (G92) cards won't support it because these cards only have 1 SLI connector. You'll also need a special 3-way SLI bridge card and 3-way SLI drivers from NVIDIA.
It might be worth it if you want to run all your games at the highest resolution and quality on your 30" LCD display but I don't think most people will go bonkers for it because of the very high price and all the bad press about the firm's Quad SLI.
Source: VR Zone