Kaiser,

http://www.overclock.net/mice/173255-cs-s-mouse-optimization-guide.html

This link is one of the better ones explaining mouse settings for gaming.  Disabling mouse acceleration and setting the OS mouse sensitivity gave me the biggest improvement in accuracy.  

Set your game res to 10x7 or 12x8 if ur widescreen.  I have a 37&quot; Dell 3011 at work (25x16 res) and UT3 looks beautiful, but I play better at 12x8 on that monster.  The enemy heads across the map are the size of peas, compared to individual pixels at 25x16.

The only other tip is to set your mouse sensitivity as low as possible.  It took me about 3 months.  I just set a low sensitivity and used it until it felt natural, then set it lower and used it until it felt natural and dropped it again and used it until it felt natural...  3 months.  Like I said, makes movement more difficult, but mid-long range accuracy will make up for it.

GL vagineer