Wolfenstein: Enemy Territory

First, make sure you have created a profile, and set the graphics the way you want them. Go to <gameDir>\etmain\profiles\<profileName>, and edit etconfig.cfg.

Edit these lines.

seta r_mode "x"
Set this to -1.

seta r_customwidth "xxxx"
seta r_customheight "xxx"
Set this to your favorite widescreen resolution.

seta cg_fov "90"
Set this according to your preference. According to the FOV calc, you should use 100.39 for 16:10 resolutions, and 106.27 for 16:9 resolutions.