Blizzard has released a preview of the Shaman Tier 13 armor set that will be available in World of Warcraft Patch 4.3. You can click on the above image to view a larger version. Here's their description of the Spiritwalker’s Vestments:
"The best shaman sets are a mix of the animal and the elemental. This tier combines huge wolf-skull shoulder pads, bone fetishes, and fur with glowing shards of amber crystal. The entire set is lashed together with lengths of rope and heavily stitched leather, which lends the set a savage bearing."
In addition to the Tier 13 reveal, Blizzard has posted a visual guide to shaman Tiers 1-12 for Transmogrification purposes. You can view the shaman's armor history after the jump, and check out Wowhead's guide to find all your old tier gear. Also, be sure to browse through all of the currently released Tier 13 previews.