The latest VirtualBox 4.2 includes support for drag'n'drop from host to Linux guests. However you might need to have a permanent mounted folder which can be shared between the host and the guest machine. In this article I have used Ubuntu as the guest virtual machine. However the same details apply to any Linux distro such as Fedora or ArchLinux. Of course you must have Guest Additions installed.
First open VirtualBox select your virtual machine and press the Settings button. Go to Shared Folders and Add a New Share. Type the Folder Path e.g. the location of the shared folder of your host machine and tick the Auto-mount and Make permanent options.
Now start your virtual machine. The folder you have shared is only accessible to the users of the vboxsf group. Therefore you must add your user in that group. Open a terminal and type:
sudo adduser $USER vboxsf
Now open a file browser in your guest machine and go to /media/sf_your_shared_folder. Your user will have read-write access in that folder.