2. select the song you want as a ringtone in the library.
3. right click and select convert to AAC
4. make sure you have file extensions showing for all files
5. you will notice the file is .m4r the one you converted, now rename it to .m4a
6. use a audio editor of your choice and edit the song to under 30 seconds.
7. make sure the tone is in the ringtone tab for itunes and your iphone and sync and then it will add it to your ringtone folder with a new custom ringtones section there.
also if you jailbreak you can just upload via SSH and the song can be over 30 seconds.. i know it never takes any one much longer then 5-10 to answer but it saves you the hassle of editing the song to under 30 seconds..