Two Graphics Cards?

I think i've seen somewhere that you can connect two graphics cards together to work in parallel. Dramatically increase your graphics capabilities, or something.

Is there truth in this? If so, any good articles? Links? How-To's?

>>8

SLI was ment to be used with 3d editing programs like 3d max or maya. It was never intended to run, not very good at running your Quake 4 game on 'OMG EYECANDY' mode.