go to options/media card and turn on mass media storage mode then you can open your phone as an external drive and drag and drop files onto the sd card
install the blackberry desktop manager plug your phone into the the usb slot on your computer then look at your phone and click enable mass storage mode then you go to you c drive on your computer, you will see either blackberry or removabable f drive. whatever it is click it. that will open up the blackberry menu and you will see a folder that says music.
drag and drop your music from your pc into that
If u have a micro sd card reader, u can use that to plug into PC and drag drop into the card
But format the card on your bb first
This creates the folders for music, videos etc
Posted from my CrackBerry at wapforums.crackberry.com
You should get a USB cable so you can just connect your BB to the PC and drag and drop. Removing and replacing the SD card in your BB and card reader is a hassle as well has an opportunity to damage the card and/or BB .