The official release of Minecraft 1.6 will be made on Monday, July 1 for those willing to wait for the final release.
The 1.6 release is officially dubbed the "Horse Update" as it adds horses along with donkeys, mules, horse armor and leads/leashes. Other new items include carpets, hardened clay, stained clay, block of coal and hay bales. Name tags have been added as well.
The other big change is that texture packs are now replaced by resource packs which can contain not only custom textures but sounds, language files, fonts and end credits without any modification to the Minecraft code. The goal is to eventually make every mod and plugin a resource pack for the game including the base, vanilla version. This will allow users to easily switch between mods and different version of the game using the new Minecraft launcher.
Those interested in downloading the Minecraft 1.6 pre-release should head over to Mojang's website now. Keep in mind that it is recommended that only experienced users download pre-release versions as there's a chance it could corrupt game saves.