If you've ticked 'share my music' within your options, then you'll be able to share your iTunes. If you don't want this, untick it & apply. When you have LW & iTunes open together, you'll see "Your name's LimeWire Tunes" in iTunes. When LW is off, you won't see it in iTunes anymore. If you've unticked 'share my music', you won't see it. iTunes needs LW to share.

Your LW shared is different. Tools > options > sharing will tell you the location of your shared LW files. Totally independent of iTunes. You can do whatever you like with iTunes but this location is where your files will be shared with other Gnutella users.

Hope this has cleared it up for you.