Cover Contest: Island of Doom

Harpercollins Canada is having a "Cover" party on my Facebook page. Just click here and enter to win (alas, Canucks only). Contest closes real soon... You're welcome to "like" my page, too, if you're so inclined.
Here's a peek at the cover. It's the 4th and final book in the series:
And for extra fun, here's the concept sketch. It has its own charm.