Almost all of my screenshots have jagged edges even though I have anti aliasing checked in flight simulator.  I decided to see if it was making ant difference at all so I unchecked it while I had the screen paused using the "alt" menu and it looked exactly the same.  What should I do?

As gijake mentioned, you should have the anti-aliasing set in your graphics card settings. It should be unchecked in your FS9 setting. If you need a more detailed tutorial, send me a PM and we can work on it..

What is that and how do i change it?

Edit: Nevermind, I remember now.  I changed it but i think that when i open FS it goes back to 800x600.  Do i change it in the game or on the computer

yeah, just after i edited my post i found that, thanks.  Unfortunately i cant resize with paint so ill have to wait untill i get photoshop elements, which should be soon.