You can't put wooden planks in the furnace, just the wood you get from the trees as the fuel. 

If you put wood both in the 'fuel' AND in the 'ingredient' parts you'll make charcoal. 

And if you want to turn cobblestone into smooth stone, put wood in the fuel part, and cobblestone as the ingredient and hey presto, you have some nice smooth stone!

You can make glass blocks too, if you put sand as the ingredient. Useful if you want to have windows in your house :)

Hope that helps, and hope you're enjoying this magnificient game!

Great news from 4J studios today, from their official Twitter feed and the Xbox website...The 1.7.3 update will be going live in 10 days! The update includes:

-Pistons.

- Fixed clay generation.

- Flint and Steel or redstone is now required to trigger TNT.

- Fences can be stacked.

- Added Shears.

- Redstone wire now will connect to a repeater.

- Shears can be used to pick up leaf blocks.

- Shears can be used to shear sheep without hurting them

- Sheep no longer drop wool from being punched, only from being killed when they are unsheared.

- New textures for Cobblestone and Brick blocks.

About time!

Niiicce. Mine is my treehouse. I searched the map for the tallest tree i could find and built a ladder up the side of the trunk. I then built a wooden platform on the top, with a glass swimming pool suspended in the air off the edge of the platform. I plan to build bridges from one tree to the other, creating a complex of above-ground walkways.

Get it for free? Yeah, i know how.

Throw yourself in front of a train. You won't have to pay a penny.