N end on the mini levels in PSP Little Big Planet

If you mean the gameplay tutorials, you can get a basic idea of that through the earliest levels, The Gardens, which will go over all the stuff like jumping/gripping/etc. If you mean the creation tutorials, if you hit Square to go to the Poppit menu, then move to the Tools Bag, then hit Square instead of X in the Tools Bag, you'll see the text from the tutorials you've finished already. If it's blank, then you still need to do the tutorial, which you then should be able to do by hitting the ? mark.

There is in the custom made levels, it came with Creator Pack 1. However, it needs to be added in by those who made the level. Most do but, some aren't that forgiving.

As for the main story levels I don't think there is. My daughter and I are on our 3rd play of it and it is something I wish was there but, doesn't seem to be.