What you need:
1: You need the orginal rom. You can't play the IPS file in an emulator.
2: You need the IPS file.
3: You need an IPS patcher.
1: Open snestool.
2: Select "use ips".
3: Select the IPS file.
4: Select the rom file you need to apply it to. Remember to make a backup of the original rom file!
5: Run the rom file you patched in your favorite emulator.
Using IPS PLUS:
1: Put ips.exe in a folder together with the rom and the IPS file. Remember to make a backup of the original rom file!
2: Go to the dos prompt and go to the directory you put everything in.
3: Type: IPS [ROM NAME] [IPS NAME]. Replace [ROM NAME] with the rom file name and [IPS NAME] with the IPS file name.
4: Run the rom file you patched in your favorite emulator.
Using ZSNES: (Only for SNES games!)
1: Rename the rom so its called the same as the IPS patch. (If your IPS is named 1.IPS, name the rom 1.SMC)
2: Put the rom and the IPS file in the same directory (or the save directory you use if you have one).
3: Load the rom in ZSNES.
4: The rom is not modified if you use this method. This method may not work with all games.