I have VirtualBox installed on Mac OS X host. And debian is being installed as a guest OS. I use folder sharing feature of VirtualBox by selecting a folder on Mac that I want to share. Then select Auto Mount and Make Permanent.
The auto mount will mount the shared folder in to media directory on debian. However this folder belong to vboxsf group. I then open root terminal in debian and run "adduser MyUserName vboxsf". After restarting debian, I can open the shared folder inside the media folder.
http://www.virtualbox.org/