Yes, if you have two SLI-supportive graphics cards. Install a 1.0-8XXX NVIDIA series drivers, and then use nvidia-xconfig --advanced-help to find the appropriate command to use. There are multiple modes such as auto, AFR, and SFR. nvidia-xconfig will write the SLI option to your xorg.conf, and then reboot. You can then check your xorg.0.log to ensure SLI is active.
Be forewarned that the Linux SLI performance generally sucks.