One of the many ways to lend that special, personalized feel to your iPhone is to add ringtones to your iPhone (and set different ringtones for different callers). This is how you can do it:

Go to the “Home” screen in your iPhone and choose “Settings”. From “Settings”,  go to “Sounds” and then to the “Ringtones” and then select from the available list of available ringtones. To assign specific ringtones to specific contacts, go to the “Phone” from your main screen, then select a specific contact and then tap on the “Ringtone” option to assign different ringtones to different contacts.

If you want to have more options than the iPhone’s default list of ringtones, go to the iTunes library first and select any track that is marked with the ringtone symbol . Select any of them and then  select “Create Ringtone”. You can now cut out 30 seconds from that track, add various effects like “Fade In” and “Fade Out” and preview and get it (either buy it, or if it is a free track, just get it like that). Now sync your iPhone with the iTunes to get the track into your list of ringtones and then follow the steps mentioned above to create a customized ringtone.