Tile should be at least an eighth of an inch over the tub and should be bonded with a pure silicone caulk.

Tim, it won't last, if what you're talking about is tiling the tub itself. In order to tile a tub, it must be constructed specifically with the idea of tiling it, right from the start. To buy one of the plastic or cast iron enamel tubs, and then tile it-- it won't last.