The LW Playlists will not import into iPod.
It depends upon which version of LimeWire (LW) you are using.
If using LW 5, the songs will automatically Add to iTunes if you enable that option in LW's preference options. Otherwise you need to add the songs manually.
For LW 4 users using windows, you need to add the song files manually.
Instructions how to add the files properly to iTunes here: How to transfer music to my iPod (& iTunes) {click on link}

When the songs are being added to iTunes, you will see them being added with a progress window at top of iTunes. Example images shown in that link. ie: song files need to be within iTunes music folders for them to be added to iPod.

Adding to iPod can be via synching playlists or done manually. See the iPod tutorials to see how to do it manually (which was my preferred method.)