Since iOS 5 you can change the iPhone SMS tone. You can choose between various pre - installed ringtones and Note and can also buy more from the iTunes Store. Even your own music as an SMS ringtone. However, this is a bit more complicated.
Pre-installed the SMS tone on the iPhone to change
To use a message tone that is already available on the iPhone, proceed as follows:
Open the settings App, and scroll down to "tones".
Click on "SMS sound" under "sounds and vibration patterns".
Select the desired note or a ringtone by clicking.
For more SMS tones for iPhone buy
Through the iTunes Store, you can download additional sounds for a fee. Here's how:
You "open settings" - "tones" - "SMS tone".
Click in the upper-right corner of the "Store". There, you can buy various note sounds at the moment one Euro.
Press the Button with the price and then "sound buy". Now enter the password for your Apple ID. The sound will be loaded directly into the settings, and you can use it as described above.
Own music as a SMS tone import
Although you can play iTunes songs as ringtones or SMS tone on the iPhone and on the desired length of the crop. But this will take a little longer and is not very easy. A detailed step-by-step instructions can be found here.
The instructions refer to an iPhone 5 on iOS 6.1.3.