I actually just tried to do that yesterday with my Android device and it did not work. When I plugged it in it simply said "usb overload" I then referred to the user manual and it said not all devices are compatible.
Hello. I've now bought one of these and the correct answer is: No. It cannot play media across your network. Nor does it make files on an attached USB drive available to your network. It can stream from the internet via wired ethernet to your router and can get firmware upgrades from it. But it has no network 'presence' itself. Of course, it can play video from a USB pen drive connected directy to it via the USB slot at the front of the machine. It only likes pen drives and cannot handle bigger USB driven external hard drives.
You can plug the USB directly into the USB port on the front of the player, and connect a network cable from your router to your bluray, and then to your computer, and you will be able to access all of the photos, videos and music on your computer's hard drive.