This is a tutorial on to install Player Skins into CS...
1.) First download a skin... again, use Banana or any other site... FPSBanana Again, you can us either CS or CS:CZ.
2.) Now you need to unzip the skin. What I like to do, particularly with player skins, is to unzip the files you need into an "Extraction Folder". I made a dummy (or blank folder) called this on my desktop for this purpose so I don't have to hunt for the files and I can manipulate the files as I see fit.
3.) Now here is a fun tip. Say you have 2 skins you really like, but they are both Urban style skins, and you want both. What you can do is after you unzip one of the files, you can rename the file another name. (ergo why you unzip to an extraction folder)
To do this, you unzip the file, in this case Urban\Urban.mdl (you need to leave the mdl file in the self name folder, why? its just the way CS is) Now go to the folder and rename it, for example Spetsnaz. And then the file itself, Spetsnaz.mdl. You don't need to open the file to rename it! Just single click it (highlight it), then single click it again, and then rename it.
Now just move the folder with the file (of the same name) to this location...
C:\Program Files\Valve\Steam\SteamApps\"yourname"\condition zero\czero\models
So it should look like this...
C:\Program Files\Valve\Steam\SteamApps\"yourname"\condition zero\czero\models\Spetsnaz\Spetsnaz.mdl
4.) Thats it! You got your skin! (A lot easier then a weapon skin)
Here is the list of names for the models used in CS. Again, make sure you have called the file and folder the same name and that the file is in the self named folder