The Harry Potter and the Deathly Hallows cover art has been released. See this article from the Leaky Cauldron for details. They have images of the covers for both the UK (Canada) and the US editions, so we also get the summary.
Mugglenet has better resolution images, just scroll down the main page to the news item about the covers.
Let the speculation begin!
My first note about the British cover - there is a full moon over Hogwarts, the kids might be in a vault at Gringotts, and there is a Patronus Stag.
The US version - could that be back in the archway room where Sirius disappeared?