This is how I made my compost box out of pallets. I even used the nails that held together the pallet.

What you'll need:

Pallets (obviously)
Hammer (helps a lot)
Saw (not the movie)

Let's get crackin' shall we?

Step 1:

Begin by hammering of the wood from the pallets and removing the nails from them.
Saw the wood into right sized pieces (i did not measure when I built it)

Step 2:

Build the box, its a bit tricky at first but it gets more stable as you go along.

When its finished its ready for compost (or whatever you want to use it for),
the best green(green stuff thats high in nitrogen such as grass etc) to brown(brown stuff, leaves etc) ratio is 1 to 2.

Remeber to add a bit of soil first to help those poor bacteria.
Water it every week, it should feel like a wrung out sponge.
Stir it with a stick once a week to bring in new oxygen.

My next 'ible will be how to make a shakuhachi ( japanese flute, the proper way)