http://www.whippedbakeshop.com/search/node/Wood

How do you do this?

Looks like edible photo sheets.

I "opened" the cake photo and it says that is hand-painted woodgrain textured fondant. May be a mat with woodgrain design was used or a rolling pin. I have both but in smaller scale. The rolling pin is 5" & the mat is 6"x6". I used the rolling pin in the wood tub of a baby shower cake in my photos here.

No it's all chocolate. See full instructions in Wayne Gisslen "Professional Baking" which you may be able to find in a public library. I think Toba Garrett may also show this in one of her books.

That really looks like a wood-grainig tool effect. Supplies are purchased in the faux-finishing section of the hardware store. It is most often done with stains. The same effect can be achieved with chocolate.

You would faux-finish a sheet of acetate with chocolate, cut to size and apply to cake.

I've never covered a cake in chocolate, sounds very intimidating! Are there tutorials on here for that?