If you’re creating your ring tone from a CD, rip the song you want as a WAV (Windows) or an AIFF file (Mac). Using iTunes, specify this type of ripping in File/Preferences/Advanced/Importing. It’s a good idea to specify a new ripping location, too, so the ripped song doesn’t end up lost in the rest of your collection. In iTunes, set the “rip to” folder in File/Preferences/Advanced/General.
If you’re creating your ring tone from an MP3, just copy that MP3 into a new folder so that your ring-tone editing won’t affect the version of the song in your digital music collection. Once you have the song as a digital music file (whether WAV, AIFF or MP3), run your audio-editing software. I highly recommend Audacity for this task. It’s free, it’s open-source, it runs on all major platforms, it rocks. If you don’t plan to use it, skip the rest of this tutorial and consult your software documentation. Audacity converts — read on!
Before Audacity can export audio to the MP3 format your cell phone wants in a ring tone, you’ll need to download the LAME library. LAME is open-source MP3 audio-compression software that rates among the best anywhere for recording fidelity. It also claims a legal exemption from MP3 patent royalties, meaning it’s free, for now at least. Find the link for your operating system listed above on this page, and download LAME to a new folder on your computer (it will need to stay there for Audacity to access it for MP3 encoding).
Run Audacity, go to the Audacity/Preferences menu, and click the Find Library button near the bottom of the screen. Navigate to the LAME Library on your hard drive, and select it. I recommend setting your bit rate to 128 Kbps. You can choose a lower bit rate to save space on your phone, but you’ll get lower-quality sound. In Audacity’s File menu, select Open and find the song you ripped for your ring tone.
You’ll see your song laid out from left to right. Click the cursor around until you find the section you want for your ring tone. You’re looking for a phrase of 10 to 15 seconds or so. Take a few passes at highlighting your future ring tone. Press the space bar to preview the selections. When you find the right one, you can export it as is — or you can personalize the ring tone with audio effects.