Have you found a solution yet? I've searched all over to try & find out how to use .mp3 ringtones I've already downloaded on this SPH-M390 (I'm sure the process is similar on other models, so after this I'm gonna go search different models. Samsung's website was useless. They say yes, but don't explain how. This guy that answered you must've left a few steps out. I tried doing what he said and putting it on the root of the phone as well as creating folders named "ringtone" & "ringtones". If you or anyone has downloaded ringtones through the phone, please look & see where & how it saves them & let me know. Off to try some more things.