I would get a NAS (Network Attached Storage). A NAS is always on.
A NAS plugs into your router and becomes a network drive, but more importantly some NAS drives also include capabilities for people remotely to add files to the NAS and get files off the NAS.
You can set up security on the NAS so people have to logon before they can get files, and you can also setup individual folder (password protected) for each person.
Note you can get a NAS for as little as £99, but these dont have many feautes so I would spend a bit more and get a decent NAS (a few hundred pounds).
The Synology DS110J got good reviews (their entry level model), more here
http://www.synology.c...ucts/DS110j/index.php
Note this only takes 1 hard disk (not included) but it may be better to buy one that takes 2 hard disks so they can "mirror" each other for extra protection in case one fails.