This is what I use for my skinning:
This is a simple tutorial on how to actually skin your Day of Defeat: Source weapons, and characters.
First of all, you want to download GCFScape and VTFEdit. I have Adobe Photoshop CS2, you can download the free trial by clicking on that link. You also want Irfanview.
Make sure Steam is NOT running.
Okay open GCFScape, and do the following: File> Open> "day of defeat source.gcf"
Okay, when you do that, two folders pop up, "dod" and "reslists", you want to open "dod". Then navigate to the "materials" folder, and go in to that. Now navigate to the folder named "models" don't go into it though , right click, and extract it to your Desktop.
Now you can close GCFScape. Now that you have your models folder on your Desktop you can easily access it. For example, go into the models folder, and do the following: Weapons> [v_models, is how you see it in first-person, w_models is how other people see it, world view.] Go into what ever you want v_models or w_models, and go deeper throughout the folder until you reach the actual ".vtf" file, then you can open that up, and do File> Export [to Desktop]. When you export it, it should be ".tga"
Now that you have successfully extracted a weapon skin you want, you can go ahead and open up Adobe Photoshop CS2, and File> Open [the name of the skin you have exported]. Then edit, or color it how ever you want, then once you done, do File> Save As> [name of the file, save it as ".tga"]
Now, open up VTFEdit and do File> Import> [name of file]. Then you'll see the image, now do File> Save As> [go to the directory C:\Program Files\Valve\Steam\steamapps\your name\day of defeat source\dod\materials\models\weapons] then go into v_models or w_models and save the file over the file you originally had there.
Now you should be able to play DoD:S and it will work.