Sure. Add A material then add a texture. Hit F6 to get to the textures buttons and from the dropdown menu under texture type select wood. then fiddle with the parameters till you get the grain the way you like. There are eight texture channels that you can use to overlay grains, clouds to break up solid color, adjust alpha and such. Hit F5 to get back to the materials section and adjust it to your mapping preferences. The old Blender 2.0 guide had a short tutorial on how to do this. I'm not sure if it's in the 2.3 Guide but I'll check. Alot of the old tuts were carried over into the new guide. Have fun~