the red balloon(s)

So, the recently-announced DARPA Network Challenge is interesting:

The challenge is to be the first to submit the locations of 10 moored, 8-foot, red, weather balloons at 10 fixed locations in the continental United States.

It's such a simply-stated problem, but how to tackle it? With a six- to nine-hour window when the balloons will be up, that's not enough time for sufficiently high-resolution satellite photography, is it? So it sounds like it's more a social problem—i.e., how do you organize sufficiently many people to find these ten balloons in a search space of the entire continental U.S.? I'm wondering whether there are coalitions forming or already formed to share the potential winnings among lookers-out.

Update: here's one group I've joined: MIT Red Balloon Challenge Team.