Originally Posted by athflying
All you have to do is copy the MP3 to your SD card, go to the music player, play the mp3 and hit menu...hit "select as ringtone" or something close to that. The mp3 will now appear as a ringtone choice.
You don't even need to go that far.
If you create a folder called "ringtones" (without the quotes) on your card and copy/dump sound files into that folder - they'll show up.
No need to use the music player.