I use this, http://www.xitel.com/product_phfl.htm , to move music from a PC to a sound system. The Xitel Pro offers digital hookup which is nice for a 60' run to a DAC with no voltage drop. My ARC converter handles three inputs, so one can be from the computer, one for a Fostex CD recorder and one for a Sony ES CD player. I haven't gone to an additional hard drive for storage.
Itunes will convert your CD's and downloads from eMusic, but not convert from Napster. Look at Napster for downloaded playlists, your or theirs, that are included in your monthly subscription.
The Napster mentioned is not file sharing, it's purchase or download, and it's a huge resource.