I have to put a lot of iPads on a stantd on a tourist fair to show our web, and we don\'t want that people can use these iPads to play/enter facebook/etc. Is for this that I
No, you cannot disable the home button. (And thank Apple for that. Who knows how many people would believe that their app is so fantastic that people ought not stop using it ever.)
Why do you need to disable the home button anyway? Why not build a stand for the iPad that blocks access to the home button?