Here's a 20 minute (yes 20 minute) trailer for it, well worth a watch. I love the accent Notch has!
A small update by Notch is out featuring the following;
+ Added a new use for bonemeal
* Changed the material of glowstone from “glass” to “stone”. This means you need a pickaxe to get resources from it
* Made glowstone drop more loot
* Made the recipe sizes for creating cloth blocks and glowstone blocks smaller (2x2 instead of 3x3)
* Re-introduced unlimited FPS, renamed the option again
* Fixed beds not working very well at all in SMP
* Fixed destroying a boat spawning the player too low, causing them to sometimes fall through the ground
* Boats float up to the surface quicker
* Boats falling down into water lose their vertical momentum very fast
* Removed Herobrine
Onwards and upwards for patch 1.7. I'm really enjoying the direction Minecraft is taking.