heres how i do it. and i luv it!
save the mp3 or acc or m4p song to your computer.
go to
http://www.youmobile.org/mms.phpenter ur # and other settings and info
select ur file
hit send!
the file will b sent to ur phone in a NORMAL text message. it should come from a place kinda like
mocheng@lg-vu.l.vu.com or sumthin.
hit options and tap "save sound as ringtone".
ur done!
GOOD LUCK!
NOTE: THIS SERVICE IS FREE. YOUMOBILE DOES NOT CHARGE FOR SERVICES. STANDARD TXT MSGNG RATES APPLY. NOT PREMIUM. NORMAL! ABSOLUTELY FREE IF U HAVE A TXTNG PLAN.