I'm going to teach you how to skin your hands in Counter-Strike: Source.
The programs I use is Photoshop CS3 Extended. You may use a lower version of Photoshop if you would like.
1 ) But in order to save you work in VTF format you will need the VTF Photoshop Plug-In.
(This allows you to save your work in Valves Texture Format)
2 ) I recommend you grab the VTF Shell Extension as well
(This helps browse VTF pictures through your windows like in Icons and such).
3) You need one last thing. You need GCFScape a program designed for browsing through Valves Cache Files (GCF stands for Game Cache File)
(A large file were all your games information is stored on and read through by the engine)
You can download the following programs in this thread.
OK After you have downloaded and Installed the programs lets begin.
1 ) Open this (C:/Program Files/Steam/Steamapps/)
After you have this open you will instantly notice that since you have install GCFScape you computer recognizes those files to be read with GCFScape.
2 ) Next find the file called counter-strike source shared with an icon that looks like this 
double-click that file.
3 ) After you have double clicked the file counter-strike source shared your computer will the the default program given (GCFScape) and when that opens you will notice its just basically browsing. What were browsing for is our hands. (Here is the directory to the hands) cstrike>materials>models>weapons>v_models>hands
4 ) Once inside the folder called hands. Extract the three files inside that folder to your desktop and close GCFScape.
5 ) Now if you have installed the VTF Shell Extension the file we need should be easy to spot out now. What we want to edit is the .VTF the VTF Shell Extension should have converted the plain ole paper icon to a nice Thumbnail Picture and can be viewed easily.
for example from this 
to this 
6 ) Open the VTF file you have extracted to your desktop with Photoshop.
7 ) Once in Photoshop you hands will appear and you can start your editing do what ever you may like with your hands. There yours. Just try to stay on the hands and don't edit to much on the black areas of the picture. This step is based on your artwork and knowledge with Photoshop.
[TIP] If you play right handed in game make sure you flip all the edited parts so that it shows up correct in game. For Example if I were to put Gamers House in small font on my wrist then I would flip it so that it could be read correct in game.
8 ) After you have finished you editing to your hands save and overwrite the existing file (v_hands)
9 ) Finally open your directory to (C:/Program Files/Steam/Steamapps/
10 ) After making all those folders finally take the three folders on your desktop and place them in the hands folder you have created.
THAT'S IT!
P.S. You can do this technique for any texture in Counter-Strike: Source.
Any questions please ask.
Here is an example of a final result I made.
