On Topic: Depends on what kind of wood it is. If it's been submerged for years and years, and it's not rotting, shouldn't be a problem. I purchased a piece of wood that came from a river that had been submerged for 50+ years.
Boiling it will kill any bugs, mold, fungus, etc that may be living on it...
Boiling it will also encourage it to break down. In my opinion if it's going to break down on me, I'd rather it do it in the cleaning proces than in my tank... Breakign down in the tank isn't the end of the world, but it creates a constant supply of particals in the water that look ugly and clog filters.
Boiling it also pulls tannins out faster. Tannins is what makes the water tea colored and is also what effects the KH?PH of the water (Tanic Acid).
Boiling it in salt water will help 'cure' the wood thus preventing or at least reducing the process of breaking down. I highly suggest boiling it in salt water if/when you boil it.
Pine Sap and a few other types of sap are harmful/deadlyto fish and should be avoided. But if the wood has been submerged for an extended period of time, chances are it would be fine (but no promises). But that being said, softwoods like Pine break down easily and typically wouldn't make good 'driftwood'.
Wood found in salt or brackish water typically make better driftwood as they have been soaking in salt water as opposed to fresh... the salt helps preserve the wood and prevent it from breaking down...
All the wood in my tank came from my canal, its been fine for me. I spray it off first with the hose just to not have the loose stuff clog my filters. No harm to my fish, although they all came from the same canal but it seems alright to me. you could boil it for safe measures.
I have been tempted to do the same. My parents live on a lake and there is a river/swamp near my house. I am sure I could find some but am not sure how long it would take to clean or if I would pick up the correct type of wood. It took over a week of soaking the driftwood that I purchased from a store to stop leaching in my sink and another week to clear up in my tank.