Mojang have released the latest client and server update for Minecraft, wolves and cookies are now included! Sadly statistics and achievement did not make it into the release, see below for full details of the changes.
Minecraft Beta 1.4
* New Minecraft logo (no longer 3D blocks).
* Added wolves that the player can tame, or kill for no loot.
* Added Cookies which heal the player for 0.5 hearts.
* Sleeping in a bed now resets your spawn position.
* Sneaking while climbing will hang on to the ladder, thus being a handy cave tool.
* Spiders will no longer trample crops and have walking sounds removed.
* Sheep can now spawn in Pink and Brown.
* Flowers and Mushrooms are much more common in new worlds.
* Cocoa Beans can be found in Dungeon chests.
* Wheat grows more quickly compared to 1.3_01
* The new default hotkey for the inventory is ‘E’.
* Added new block, Locked Chest, which was an April Fool’s gag. It linked to the Minecraft Store.
* SMP servers can now have a new world seeded with an option in the Server.properties file.
* Lots of infrastructure for Statistics lists and Achievements have been implemented.
* Scale of UI may now be changed in options.txt located in the .minecraft folder.
* Zombies and Spiders now hurt you in all instances.