Go to <gameDir>\system. Open ut2003.ini. Find these lines:
Change them to set your resolution.
**IF YOU HAVE A 16:10 DISPLAY**
Now open user.ini. Find these lines:
Change the values to set your FOV to your preference. I recommend 95.
**IF YOU HAVE A 16:9 DISPLAY**
If you have a 16:9 display, I recommend an FOV of 102. Unfortunately, if you set the FOV to something higher than 100 in user.ini, it will get reset to 100 as soon as you load the game. Instead, whenever you load a new map, bring down the console (the tab key does this by default) and type "fov 102." This seems to work in all online games. Advanced users may consider binding a key to "fov 102." If you don't mind having a slightly too narrow FOV, you can just set the FOV to 100 via the user.ini file.
The game's aspect ratio automatically matches your resolution. But the wider your aspect ratio, the higher the FOV needs to be to maintain Hor+.