Enemy Territory: Quake Wars

Find the ... etqwconfig.cfg ... in (Vista) ... C:\Users\User Name\Documents\Enemy Territory Quake Wars Public Beta\base ... open it with WordPad

Change these lines:
If your resolution is 16:10 or 16:9, then just start the game and select your aspect ratio from the ingame options screen, and that's all you need to do. If it's something else, then you need to do a little math.
Write your resolution as an improper fraction, with the horizontal number on top and the vertical number on the bottom. 1280x768 would be 1280/768. Now simplify the fraction. 1280x768 would become 5/3. Once it's simplified, the number on top is your H-value, and the number on the bottom is your V-value.
eg
seta r_customAspectRatioV "1"
seta r_customAspectRatioH "4"
seta r_aspectRatio "-1"
seta r_customHeight "1024"
seta r_customWidth "3840"
seta r_mode "-1"