A friend of mine asked me this question and I told him if I took time to figure it out I would blog it and send him a link – there may be several ways to accomplish the task of setting your ringtone to use an MP3 but you can’t select an MP3 from the ringtone menu (home screen, settings, sound & display, Phone ringtone).
So how do you do it? I wouldn’t call it intuitive, but I would call it simple. Open your Music player, navigate to the MP3 you want to use as a ringtone, hit menu and select “Set as ringtone”. Yep – its that simple!