With intel theyve developed a new kind of motherboard with 2 pci-express slots. Its capable of taking 2 pci-e graphics cards and running them together in "afr" mode (alternate frame rendering). Basically one card draws the top half of the screen and the other card draws the bottom half of the screen, seems a little similar to scan line interleave with 2 voodoo 2's linked together.
Supposodly this can work with 2 different kinds of cards, nvidia and ati cards could be used together in one system to get a big performance increase in games.
http://www.pcper.com/article.php?aid=43