I found these instructions and have verified myself that it works perfectly. I can’t imagine that there is an easier way than this; enjoy!
You can actually make your own ringtones. No websites/external softwares needed.
However this does not apply to the songs you donwloaded via itunes. If you get the tracks from other sites or ripped from your CDs this will work like magic.
1. Pick your song you want to turn into a ringtone in iTunes.
2. Right click>Get Info or File>Get Info or Apple>I.
3. Go to Options when the Get Info window opens.
4. Click the check boxes to initiate Start and Stop time, manually entering the start and finish time of the song you want as a ringtone but MAKE SURE IT IS UNDER 30 SECONDS!!!
5. Now, hit Okay.
6. Next, go to Advanced>Convert Selection to AAC, this will create a copy of the song, but just the portion you want as a ringtone. If it says “convert to mp3″ isntead, just go to preferences to change it to AAC and you’ll be fine.
7. The copy will be right under the original in iTunes, you will see the difference in times with the selection you chose should be at a ringtone length, like :30 seconds or so. Right-click on the selection and choose Show in Finder, or File>Show in Finder, it should be an m4a file.
8. Simply click on the file name to edit it and change it to an m4r, this will change it into a ringtone to be recognized by iTunes.
9. Go back to iTunes, find the short selection of the song that you converted to a ringtone and drag it out of iTunes to your desktop.
10. It will make a copy of it and it should now be in your iTunes and desktop. Then, back in iTunes, delete the selection you just moved to the desktop.
11. Double-click on the file you dragged to your desktop and it should open up and play in the “Ringtones” section of your iTunes.