Don't get confused!!! Just because you see the LW Playlist in iTunes does not mean they are in iTunes music library. The LW playlist is simply a playlist that can be played but not copied or burnt, & simply reflects what audio songs you have in your LW download folder. To get the songs into iTunes music library, see How to transfer music to my iPod (& iTunes).

Then, once the songs are "actually" in iTunes Library (you can check by clicking on Music & seeing if they're there ... use the date added column & arrange them that way to be sure they were added), after you're "absolutely sure" the songs are in iTunes then you can delete them from the LW downld folder.

The difference between iTunes & most other audio programs is iTunes has its own music library where it stores music files. Whereas most other players such as WMP are simply playlist players. eg: WMP does not create its own folder to store audio files added to it like iTunes does.

The moral of this is "ignore" the LimeWire playlist you see in iTunes. It is simply a playlist & has nothing to do with music being added to iTunes. Also, don't forget to share back. At the bottom of the link I gave above are instructions on how to share iTunes music folders, which you can do for albums or artists.