ahoy! neee has come!
first, you can get the utilities need here
http://www.slackiller.com/hlprograms.htmscroll down and click the respective sprite programs you're looking for: Sprite Wizard and Explorer to create sprites, and Sprite Viewer to, well, see them
1.) for this I will refer to Sprite Wizard
open it after dling and click next. Since you want the crosshair image u posted as an LMG crosshair, click Browse after clicking Next right after opening the program.
2.) Browse for the crosshair of your choice (btw i like that crosshair) and click ok (you'll need to make it a BMP file first (just use MS Paint. it needs ot be a 256 colour bmp file!
3.) click Next. This will put it in the list you will see, with the filename. since you're making only one crosshair sprite, you wont need to add anymore bmp files (unless you plan to proceed to customizing weapons)
4.) Click Next again. It will then ask what transparency and such. choose Index Alpha.
5.) It will show the crosshair in sprite mode. Check it to see if its the right one, any errors, etc.
6.) save it as "xhairmg" without quotes
7.) insert into your ns folder/sprites. REMEMBER TO BACK UP ORIGINAL!
8.) try it ingame
9.) ENJOY! THATS AN ORDER, SQUAD 5!