I just got my clutch replaced in my car. The clutch would squeak when I would engage it. If it is squeaking take it to the dealership ASAP. I ignored it and my clutch went completely out. As in, I put it in drive and heard a loud clunk with the clutch stuck to the floor. I have a brand new clutch assembly now and no squeak or anything. I'm pretty sure I know the main the cause of it.
We have two pretty decent size holes and you can clearly see the clutch/flywheel. Dirt and grime can easily get up in there which is what happened to mine. My clutch was so far gone with less than 50k miles and was full of dirt. The dirt got caught in the back of the TOB causing the squeaking which ultimately led to the failure of my clutch.