The one thing that absolutely stinks in the multiplayer is the crosshair.

How could I change/mod it? Anyone change their own yet?

I think you need a program that comes with SourceSDK to do that. Not positive of this though. I have tried changing the material source for the crosshair but I failed. It might be because the game loads the material in the MM_MP_Materials.gfc file. I need to find a way of changing the source material here to confirm this.

It doesn't come with the source sdk, but you DO need a program to open the .gcf files (gcfscape). A .gcf is basically a giant .zip or .wad file that contains all the stuff the game needs to run, or whatever the file name is. After you get into it, you may need a VMT plugin for photoshop which can be found on FPSBANANA.COM somewhere.

Opening a .gcf file with gcfscape is one thing. Changing the content is an other...