i actually googled this yesterday. the main consensus was:
1. wrap it tightly in plastic and bury it as far from your home as possible at least six feet underground
2. leave it in an area where animals (esp. pigs apparently
) or alligators would devour it
3. (this one is really gross) put it into a large drum of acid in a secluded area of your home and then carefully pour this down your garbage disposal
4. fill a large drum with the body pour cement over, go out late at night in a boat several miles offshore and drop it (something about if you do it right the body will decompose create an air bubble pop the drum and the concrete will disperse into the water).
5. woodchipper (fargo, anyone?)
me personally, i might try the "Weekend at Bernie's" approach lol!!
i hope this post is not offensive, it's kinda meant tongue in cheek, the only things i've ever successfully killed are some geckos which met their demise squished in the side of my back door and the random cockroach/fly/skeeter.