Minecraft version 1.2 (actually 1.2.1) is now officially released! Get it by updating the game in the Minecraft launcher. Features include:

New jungle biome
Added ocelots
Added cats
Added iron golems
New AI for mobs
Tame wolves can have puppies
Villagers will have children if there is room in their village
New map height limit (256 instead of 128)
New items and blocks
Doors have been updated so that double-doors work better with redstone
Added rare drops for mobs
Many other minor tweaks and fixes
In addition, the Minecraft launcher has been updated. The new launcher should properly select 64 bit Java installations for Mac OS X users. If you haven’t downloaded Minecraft yet you can grab it here: www.minecraft.net/download