http://www.pathibhara.com/using-ringtones-iphone/

I have an iphone and instead of using the ringtones already in the phone?
Can I use songs from my itunes as ringtones?
ok now how do u set the timing right in the start and end time boxes so it’s 30 seconds? i punched in 0:30 but it did the whole song not just 30 seconds.
i have an iphone
and i use this free site to get my ringtones
http://www.ventones.com
all you do is this.
1) download your favorite song from limewire or your favorite mp3 downloading program
2) upload the mp3 file and use Ventone’s FREE Ringtone Creator
3) after you’ve made your mp3 ringtone, go to your “My Ventones” page where you will see your list of created ringtones. Click on the ringtone,
4) That will take you to the ringtone page, scroll all the way to the bottom, where you will see a link that says
“Click here For your Iphone Ringtone”
5) Click on that, and in seconds you will get a link for your Iphone ringtone download. Download the file onto your computer.
6) Go to itunes, and Import the iphone ringtone that you downloaded from Ventones and you will automatically see it listed under Ringtones category in iTunes(my library)
7 ) Connect your iPhone and Sync the Ringtones.
FREE RINGTONES FOR IPHONE USING iTUNES