I found a mod that uses SMAA as a standalone and I am not sure what it does because it doesn't have a descrition.

Also, I have an ATI card, are there settings in the Catalyst that I should change?

It's a high performance but quality form of AA. Yes, you should use it over the ingame AA or AA forced through your video card.

Ati catalyst has a setting to turn Morphological Filter on...should I check this?

Leave that unchecked if you want to use SMAA.

Here's some testing I did a while back with this:


Screenshots

http://www.imagebam.com/image/84021b163595823
http://www.imagebam.com/image/7733af163595851
http://www.imagebam.com/image/82cd55163595889

http://www.imagebam.com/image/86530c163595914
http://www.imagebam.com/image/958234163595925
http://www.imagebam.com/image/b30f9c163595935

Performance
As the game is so CPU dependent, and performance is bottle-necked by it for me most of the time, I see no point in measuring FPS, as it stays the same in most if not all situations when comparing anti-aliasing modes. So here's some GPU load percentages for you. They were measured in http://www.imagebam.com/image/1b192b163595954, which was giving me constant 80 FPS in all AA modes (evil CPU bottle-neck).

Configuration
CPU: Core 2 Duo E8200 (3.8 GHz OC)
GPU: ATI Radeon HD 6850 1GB (950/1175 MHz OC)
RAM: 4GB DDR2 800
Vsync and iPresentInterval are both turned off. (Only for testing)

GPU Load
NoAA ~70%
FXAA ~79% (+9%)
SMAA ~95% (+25%)

The traditional 4xMSAA seems to be almost on par with NoAA (maybe around 2% more GPU load), but it obviously eats loads of VRAM. For example, playing with 1920x1080 and 4xMSAA increases VRAM usage from ~650mb to ~950.

So if you have enough VRAM and need GPU power for something else, say ENB, I'd go with MSAA and vice versa for SMAA.