Currently running the following setup and i was thinking about adding another 226bw but im unsure if the 8800 gts will be able to handle them both. I'd like to keep the resolution the same as well.
 
Gigabyte P35-DS3R
Q6600
8800 GTS 320
2GB G. Skill
Seasonic M12 500W
Samsung 226BW @ 1680X1050
Vista
 
 
Thanks.

What are you planning on using the dual-screens to do?

my 6600gt 128Mb allowed me to happily run a pair of 1280x1024's and was not bothered by gaming in one of them, even had X2-the reunion running on both at one point. You'll be fine.

^ Supreme Commander is also blast with two monitors, one for the map and the other for zoomed-in unit direction and eye candy.  It loves four cores too, more CPU than GPU reliant.

Uses will include gaming and movies, gaming and internet, autocad and internet, and photoshop and internet. This is all on a 10k Raptor as well.

my 7800gt, and my old fx5200 handle dual monitors with ease.

For a desktop it will be fine. Games, especially newer games you will have issues because the GPU resources are being split between the two outputs.