Quickly Setup Virtual Box Shared Folders In A Linux Guest

Step 1) Setup the shared folder from within the virtual machine's settings.
Step 2) Boot up your virtual machine, and add the following line to the file: /etc/rc.local

mount -t vboxsf -o uid=USER_OWNER,gid=GROUP_OWNER SHARE_NAME MOUNT_DIRECTORY

USER_OWNER is the owner of the mounted folder. This will give the owner full read and write access.
GROUP_OWNER is the group owner of the mounted folder. The group will have read and write access.
SHARE_NAME is name of the virtual box share name.
MOUNT_DIRECTORY is the mount point of the share.

Example: mount -t vboxsf -o uid=john,gid=john VBoxShare /home/john/VBoxShare

Voilla! Easy file sharing from your host operating system and the Linux client.