Make you own ringtones from your favorite music using iTunes 11 for free

Download iTunes 11 for free and add your fav music files the library.

Select the song you like most and also select the part of the song you like most, as you can only select the duration of ringtone from 20 secs to 30 secs, as it valid ringtone

Select the song, right click and choose 'Get Info", then go to 'options' then select start and stop times and make sure the duration between 20 and 30 secs. Click 'Ok'

Then again right click the song and select 'Create AAC version', the AAC version with the selected version is created. 

Right click the AAC version file(newly created) and select "Show in Windows exploer" / "in Finder" for Mac, Copy the file and paste in some other location.

Rename the file and change the file extension from .M4A to .M4R

Again the .m4R file to the iTunes library.

Connect the iPhone

Go to the iPhone menu

Go to Tones menu, Check "sync Tones" and also select "All tones", and click on "Sync"

After the Sync is done, take iPhone, go to Setttings, then Sounds, then Ringtone, then select the desired ringtone.

Thanks and Bye,

Ravi Shankar