Forcing Resolutions ... Unsure

[chrase13]

I have a rather decent PC setup, I am wondering how I can force my display resolution in game to 2560x1440 or around that area. I have crossfire 6950's and a 3930k oc'd to 3.20gz with water cooling. I see a lot about people forcing the resolution but I knew Tom's was the place to be so I wanted to start here.

 

[chrase13]

Notes I didn't add. Using a 42" HDTV as a moniter. Not sure if that would matter considering the resolution would be forced.