You will need a PS3 and a pc, + your DNS-323. Install the software for your particular OS (linux, mac or windows) from the link above. I have my DNS-323 as drive Z.
Make sure within configuration menu of 323 (Advanced Tab) you have enabled the UPnp AV server, folder 'Root' checked off.
Also enable the iTunes Server and folder 'Root'
Here is the Apple iTunes for Windows link for 'Moving your Itunes Media folder'
http://support.apple.com/kb/HT1364
It will another page if you use a mac. This process will take a while.
Within Navigation/Share Setting tab of Java PS3 server application place your folders you use (mine were Z:\iTunes Music, Z:\Photo, Z:\Video)
Then I restarted pc, PS3 and then started Java Ps3 Media server application, then everything worked.