Jens Bergernstern, better known as Jeb on Twitter and the lead designer of Minecraft, has released the latest 'snapshot' of the game which includes a number of bug fixes and some interesting new features.
Notably, the new snapshot (12w34b) fixes item frame crashes, nether portal stuff, and changes the button-crafting recipes for both Stone and Wood. To save you some time, here are the recipes to craft the two buttons:
Stone Button
Wood Button
The changes are straightforward and easy enough. In addition to these small changes, fire arrows can now be used to activate TNT so you'll be able to blow things up at a distance. To create a fire arrow, simply shoot arrows through lava or use a bow enchantment called Flame I.
Finally, the new snapshot adds a new creature called the Wither Boss which carries 300 hit points and fires explosive projectiles at players that not only deal area-of-effect damage but also poison you with a "Wither" effect that turns your hearts black and drains your health over time.
You can download the snapshot from Mojang here.