Be sure you not to get driftwood from anywhere polluted. The toxins would probably leach into the wood and be pretty difficult to clean out. In an aquarium, dirty wood could kill everything.
I used a metal bristle brush to scrub a layer of wood off, then boil it (if i could) and bake it (if i could) and then some more scrubbing and boiling.
I've never used the bleach and water method though.