Heres how I went about it.

Ok so first thing I did was on my PC updated to Windows media player 11......that was free & simple.

I then switched the PS3 on.
On the PS3. Go to settings:-
Select Music - then search for Media servers -
It will scan and find the "name of your network" in my case "Sky-----"

A box then appears(under music & search for media servers) showing the Media player icon and beside it the name of network. In my case "Sky---"

Ok so having made a note of the network name "Sky---" in my case "whatever name of network" in yours.

Then open media player on your PC and click on the arrow below LIBRARY
Click on Media Sharing
Tick the "Share my Media To" box
To the right of that click on settings
At this point enter network name "Sky----"(in my case) into the Share media as box.
Click Apply and then OK.

That should be you done. An icon now appears.

At the PS3 click on Music - Windows media player - Playlist and thats you hooked up......or should be.