I will see what I can do to help ya...

Open LimeWire
Go to Tools (A menu option at the top of the LimeWire window.)
Choose Options (A window will open.)
Now click on Sharing.

(LimeWire, by default, chooses the file you download to as your shared folder. Some people, myself included, remove this file from being shared. That way we can check the files we download to make sure they are ok before putting them back out there.)

Moving on...

Click on Add. At this point, you can browse your Hard Drive for your iTunes Music File (within the LimeWire Options window). You will double-click on each folder to open it. When you get to your music folder, highlight it (by clicking once on it) and then click Select.

Then click Apply.
Close the Options window.

You're done! Now expect LimeWire to take some time to hash the files. This will take a while depending on how many files you have. They don't just all show up. LimeWire may run a little sluggish during this time. But, don't close it out. Let it finish. Once it's been done once, you won't have to go through it again. Unless you move some files around or add more files to share later. But, it will just hash the new ones, not all of them again.

I hope this all makes sense. I'm posting this from memory. If you have any more questions, please post back.