Changing SF4 PC Skins
1) Download whatever skin file you want (.emz file)
2) Find your SF4 Characters directory.
Retail version: "C:Program FilesCAPCOMSTREETFIGHTERIVBattleChara"
Steam version: "C:Program FilesSteamSteamAppscommonstreet fighter ivBattleChara"
3) Go into the folder of the character you want to change. Remember they are Japanese names so Boxer is "BSN" (Bison).
4) Whatever the .emz file you download is called, make a backup of the old one first. For example, Chun Li's file is "CNL_01_05.col.emz" so rename that "CNL_01_05.col.old" and copy the new modified one from the zip file in there.
5) Load the game and pick the proper character/color to see the skin (more in notes on this). Enjoy!