Cocoa Beans

Cocoa Beans (also known as the Brown Dye) are a material used for making Cookies, introduced in the Beta 1.3 update but were not able to be found without a Inventory Editor. Cocoa Beans have a dark brown, patchy texture and can also be used to color wool. You can actually get brown wool from brown sheeps that's spawning naturally in the 1.4 update. They sometimes appear in dungeon chests.

Notch has hinted sometime in the future they will be able to be grown.