For mac, you can make LW set so iTunes auto imports the songs. See
Settings within LimeWire & iTunes for auto import ... If you wish to transfer them to iPod, then I'd recommend manual updating of iPod, see
How to transfer music to my iPod (& iTunes) {click on link}. See last post on page I think that has a sample image and video about how to manually update iPod.
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Check all the iTunes tutorial videos on that page.