How to set my music as a ringtone on my iPhone 4s?

Is it possible to just choose one of the songs i have on my iPhone and set it as a ringtone?

This is how.

1.go to settings

2.click on sounds

3.click on ringtone

4.buy more ringtones

5.buy a ringtone you like

6.click it in settings

7.enjoy!

You can also use the app "Ringtone maker"
or try this
Select any song on your device to act as a Ringtone.
No Audio/File conversion needed.
Select start and ending point in song to play as Ringtone.
Easy to use interface.

Unfortunately you would have to buy the ringtone in the ringtone section of itunes.