How-To Guide: Creating a Ringtone from an MP3 for your iPhone
Note: I have done this on the iPhone 2G and 4G and I'm pretty sure it would work for any model.
DISCLAIMER: If you follow my guide to create your own ringtones for your iPhone, you do so at your own risk. I am not liable for any resulting damage or expense. I do not work for Apple nor am I affiliated with the corporation in anyway.
STEP 1:
Select an MP3 you wish to convert into a ringtone. This may be a clip from a song or a sound downloaded from the internet. http://soundfxcenter.com/ has several sound effects to chose from if you're browsing for something in particular. Keep in mind that you want to keep your ringtone reasonably short and you may have to use a software tool such as MP3 DirectCut to clip a section from the original MP3.
STEP 2:
Add the MP3 to your iTunes library. Select the MP3 in the playlist and go to Advanced and select Create AAC Version.
STEP 3:
If you are using Windows XP, locate the newly created AAC file. It is usually located in the My Music folder, which is located in My Documents. From there, go to iTunes > iTunes Music. You'll then find subfolders for the Artist and Album, which could very well be titled Unknown. Here's the full path for example:
C:\Documents and Settings\[User]\My Documents\My Music\iTunes\iTunes Music\Unknown Artist\Unknown Album
If you are using Windows 7, you can go to Libraries > Music > My Music > iTunes > iTunes Media > Music. Here's the full path for example:
C:\Users\Andy\Music\iTunes\iTunes Media\Music
C:\Users\Andy\Music\iTunes\iTunes Media\Music
STEP 4:
Now that you've located the AAC files on your computer, you need to rename then. You'll probably want to show hidden extensions for filetypes to make renaming them easier, or if you're a novice, I think it should still show up when you right-click on the file and go to Properties. The file should currently have the extension .m4a. We need to rename it to .m4r.
STEP 5:
Next, locate the iTunes ringtone folder. This is also in \iTtunes\iTunes Music\ and it should be a folder name "Ringtones" or "Tones". Move the .m4r file to this folder. Here is the full path:
C:\Documents and Settings\[User]\My Documents\My Music\iTunes\iTunes Music\Tones
Once you've moved it there, simply open it and it'll be added to your Ringtones within your iTunes program.
STEP 6:
Sync your iPhone and you should be good to go!
This process is very simple and the best part is, it doesn't cost you anything. Hope it works for you and enjoy!