In the past if you wanted a white (or any other color) crosshair in Counter-Strike: Source you had to download it from somewhere and install it. Well now you can easily have any color crosshair. Just open your console and type these four commands:
cl_crosshaircolor 5 <-- allows you to customize colors
For the example I used 255 for the RGB commands. This way you would get a white crosshair. If you want to know what numbers you have to enter for a specific color go to COLOR CODES. Remember that you have to enter the DECIMAL (R;G;B Dec) parameters and NOT the hexadecimal.