have you installed desktop manager on your PC yet? there are many ways to transfer mp3's...but you have to be careful bc if you are saving them as ringtones, they may not work properly. you need to make sure they are small enough OR that you have a media card.
you can transfer thru media manager, an application loaded into desktop manager
you can drag/drop by pluggin in to usb and opening windows explorer
you can visit websites with mp3 ringtones and download them straight to your berry (www.mobile41.com) or (www.tuneusin.com)
welcome to the stacks