A while back Asrock published a SLI enabling patch for their ULi chipset based motherboards that have two PCI-Express slots. Various rumors suggested that the patch would also function under other chipsets as well, and allow users with other chipsets to use SLI on their non-SLI motherboards. Unfortunately the original version of the patch installs only on ULi 1695/7 chipsets – you couldn’t use it if you didn’t have a motherboard with that particular chipset.
You can grab the patch over at NGOHQ.