Just figured it out.

Under iTunes "File" menu, select "Add to Library..." and navigate to the MP3(s) stored in the LimeWire "shared" folder. Highlight the MP3 file and click the "Choose" button.

iTunes presents a dialogue warning that the file itself will not be copied, etc and suggests copying it to the "Music" folder. Just click "OK" and the MP3 will show up in your iTunes library.

Anybody know how to easily move MP3s from LimeWire to the "Music" folder under OSX? I'm not too OSX savvy, and would like to create a simple method for my kids.