Network accesses must follow some common protocols, in this case Samba, not normal file system formats because different OSes cannot understand each other's specific file systems and they don't have access to the low level sectors of drives on the other systems either
The shared folder appears in my computer's network branch just like a shared folder from windows
http://windows.microsoft.com/en-us/windows/create-shortcut-map-network-drive#1TC=windows-7
After powered on the virtual machine you can manually map the drive like in the above picture. Or if you select auto mount when creating the shared folder then it'll be mapped automatically. I haven't used virtualbox for a long time so I'm not really sure about this but indeed VMWare will automatically map the network drive if you select the option
