If you are talking about your custom ringtones, then yes you can just drag and drop them over from your blackberry. If you are talking about the ringtones that come preloaded, then you can try the file at this site. Default Blackberry Notification Sounds.
Copy all mp3 files that you want as ringers to SD Card/Media/ Audio/Ringtones and they will show up in usual ringer selection menu..... Also you can place them in Notification folder if you want to use them a mail, text or other notifications.