Not only that ability, DockHide also offers another thing like measuring the app icons space accordingly when you hide the dock, this to optimize the freed space.
Currently you can get DockHide under ModMyi repository as free download. You won't find no Dockhide icons after this tweak installed on your iPod touch, iPhone or iPad. Configuration menu can be found on your stock Settings app. And the menu is simple, only two menus are provided (see the image above !).