i found it in the woods. well i saw a chopped up tree in the woods as i drove past so i parked up and wandered in, then walked back to my car with it down the main road. i did get some funny looks
Wild-collected specimens can always carry parasites. I'd recommend sunning it for a few days and then submerging it in boiling water for several minutes. Once that's done, submerge it in a large pail to check for tannins escaping or to see if it's rotting.
My 2p worth, if it's wood from a tree and it's not bogwood, it's probably going to start rotting very quickly. There's also the added concern that pesticides may have been used in the area. Trees pick this up very quickly and if the toxins aren't removed, they will leach into you water. I personally wouldn't risk it, but to each his own!
Good luck with whatever you choose!
Edit: On closer look, that is magnificent! I'd be sorely tempted myself...
There was another thread on this subject somewhere that i was reading this morning, its very recent. Have a look, i think someone posted a really good intro to "getting your own wood", and how to clean it.
EDIT: Here you go - http/www.fishforums.net/index.php?/topic/369823-found-an-awesome-new-piece-of-wood/