Yes, LW is a file sharing application. Here are some links with info, if you do decide to give LW a try then make sure to read the FAQ & User Guide before you get started
LimeWire - Wikipedia, the free encyclopedia
LimeWire FAQ and User Guide

If you use the forum search here as well (search option's up the top, between New Posts & Quick Links), you'll be able to look through past threads...heaps of info here! There are sticky threads in each of the different sections that have answers to commonly asked questions.

If you do download LW, make sure to download only from the official site.
Lime Wire » Download LimeWire
Start off with the free basic version first, don't even think about buying the Pro version until you're sure you're happy with LW. If you ever do decide to buy Pro...please, please save & back up your Pro installers

And if you do start using LW & don't want it starting up as soon as you turn on the computer - tools > options > advanced > system startup. Untick 'run on system startup' > apply > ok!!