iPhone ring Tones:

Through the settings screen under Sounds – you can choose a ring tone for your iPhone. Selection is not great (what most wouldn’t expect) and I’m sad to say that there is no option to just select one of your MP3s on your play list and make it your direct iPhone ring tone.

Never the less there is three ways to get better ring tones;
1.    you can buy a song from iTunes and can convert it to a ring
      tone directly from your iTunes.
2.    You can get a ring tone application that includes numbers
      of new ring tones.
3.    (recommended) You can download software that converts mp3s
       to 30 second ring tones (I recommend "iPhone Ring Tone Maker")
       and will send them to itunes (after syncing the new ring
       tones will appear on the ring tone section through settings).

 

Next:  8.The iPhone’s iPod
The Friendly iPhone user guide Menu