Bone

Bones are items dropped by Skeletons when they are killed. When skeletons are killed, 0-2 bones can be dropped.

Uses
Bones can be used to make Bone Meal, which serves three purposes:
 * It can be used as a fertilizer for farming that immediately makes plants grow to their mature state.
 * It can also be used to grow Tall Grass, Flowers and Mushrooms. When used on Mushrooms they become as tall or taller than trees. However, Bone Meal is not guaranteed to work 100% of the time when used as a fertilizer.
 * It can act as a dye that colors a sheep's wool white and can be combined with other dyes.
 * Another one of its uses is feeding (not necessarily one bone) it to a wild wolf, who will then become tame, and will kill any mob that attacks you via melee.

As a Crafting Material
Bone creates 3 Bone Meal when put in the crafting table.

History
As of Beta 1.4, bones are used to tame wild wolves. In most cases, more than one bone will need to be used on the wolf.