Minecraft has updated to version 1.2. It doubles the map height limit so you can build even bigger towers, adds the new "Jungle" biome, and brings cats, ocelots, and iron golems. The golems seem especially useful, since the update video shows them fighting on the behalf of the adventurers.
Other features in the update include improved AI and rare drops for the mobs, better double-door functionality with redstone, new items, and various other tweaks. You also might detect some love in the air as we enter spring, since villagers can have children if there's room in the village, and tame wolves can have puppies.
When you get the update, you'll notice that it's 1.2.2. Mojang Specifications quickly issued a minor update, since 1.2 nixed some tree types from the landscape. You can check out the 1.2 trailer below.