How to set a song to a message tone!!!!!!!?

ok so i have the sgh-t919 and i want to set a song as my message tone but i cant do that cus i got all my songs from itunes and they dont have any mp3 songs. so whenever i try to set a song as a message tone it says i dont have any song in my music folder but when i go to the music player on the app menu i can hear songs so wat can i do pls help me thx peace!!! and whenever i try to turn on my bluethooth it says "no bluethooth address!! if you dont change your BD address, it may do the wrong action '' wat is that supposed to mean pls help !! and thx again !!!! also wat does BD address mean???????? thx!!