Internally we use a product called cloudstor ($179 for 2 TB, $249 for 4TB) that can be shared, files uploaded, downloaded - basically our own Dropbox, but no ongoing fees. We also use it to upload and download customer files. Our Internal Help Desk, OS, Drivers, Software Upgrades all accessable form any computer. The files can be accessed by any smartphone or iPad using pogoplug. The files could only be accessed by those who know the link.
http://www.buffalocloudstor.com/
http://cloudstor.pogoplug.com/ for tutorials