First thing to say is, I used the "US" (United States) ROM version for all the Pokemon games, so you'll need it too. Because if you use a ROM that is half-translated or a version other than the US (like Japanese, French, Italian, Spanish, etc.), then it will never work.
You'll need a emulator like REW, which is the one I used to make the .sav and .st0 files and is the only emulator that can read and write .st0 files (you can download REW from this site by clicking here ). Now, if you are going to use REW then you'll need to edit the "rew.ini" file (which will generate itself after running "REW"):

Now the following is a "step by step" for REW which will tell you exactly what you should do in order for every thing to work properly:

  1. Open your rew.ini file with any text editor (like Window's Notepad).
    Note: The rew.ini file will create itself in the same directory where you have placed rew.exe and it will create itself after you run "REW."

  2. Once you have opened the rew.ini file, go to where it says "RomPath:" and replace the existing path with the path where you have placed the ROM. Example:
    RomPath: C:\Games\Rew\Roms


  3. Go to where it says "GBSavePath:" and replace the existing path with the path where you have placed my .sav or .st0 files. Example:
    GBSavePath: C:\Games\Rew\gbsave


  4. Go to where it says "GBStatePath:" and replace the existing path with the path where you have placed my .sav or .st0 files (replace with the same path you used in the step above). Example:
    GBStatePath: C:\Games\Rew\gbsave

  5. This step is IMPORTANT:
    Now rename my .sav and .st0 files to the same name of their corresponding ROM. (My .sav and .st0 files must have the same name as their ROM, this way the emulator (REW) will know which .sav or .st0 files belongs to which ROM)
    For example: If your ROM is named "crystal.gbc" then rename my .sav and .st0 files from "pokecrystal.sav" to "crystal.sav" (Be shure that you don't change the extensions, just change the names.)


  6. Finally, run "REW", load the ROM and to use my .sav file just choose continue from the starting menu IN the game.
    And for using the .st0 files, simply go to REW's menu and chose State and then slot 0.