Which version LimeWire? Which music program are you talking about?
For LW 4, see : Using Library Explore button to access downld folder (click on link). For LW 5, see http://www.gnutellaforums.com/gettin...file-disk.html

If you are using iTunes, for LW 4 you can add them to the iTunes music library via these techniques: How to transfer music to my iPod (& iTunes) {click on link}.
For LW 5, you can set in LW's Option settings for iTunes to automatically add the songs to its library.

If using a player like WMP, then you can simply add them to the WMP playlist; http://www.gnutellaforums.com/tips-t...rning-cds.html