Just to make sure, I've downloaded some more mp3's during the night and checking things this morning the item has been transfered into my Documents/iTunes/iTunes Music file and also appeares in the listing in LimeWire Library.

[In LimeWire, under Tools-Options-Sharing-Shared Directories make sure you have chosen /iMac HD/Documents/iTunes/iTunesMusic/ as one of your Shared Directories?]

Then in LimeWire;

When I highlight the item in the Search/Downloads window I click the Launch button and the tune appears in the iTunes song list and starts playing.

Magic!!!!!!!?
(i'm not a techy)