Problem being that if you use itunes, and a PC as a media server you can't stream that itunes music on for example a TV, PS3 etc that can access your PC media server.
I found a neat way of doing this (I think) although I haven't tested it thoroughly yet (whether the tunes in questions will work on an ipod) but the streaming part does work, as long as itunes folder is part of your media sharing folders on the pc. You can even create playlists using windows media player that will be viewable in this case by the Sony TV or I believe playstation 3.
I changed the default import to mp3, and allegedly apple have now stopped protecting their music, although their may be some conversion required - I'll try and dig out the links if anyone's interested.
I got it working at least for importing CDs on my Dads home network and Sony TV recently, and hought it might be worth sharing to CL for anyone who might need
this link talks about apples copy right protection
http://www.guardian.co.uk/technology/2009/jan/06/apple-drops-itunes-copy-protection
more links to follow re the import settings etc
this contains some useful stuff
http://askbobrankin.com/convert_itunes_to_mp3.html