In a nutshell, for now you can go to the site and download a KML file to load into Google Earth 5. This file shows you where the Mars Odyssey spacecraft is going to be orbiting over the next week, and lets you suggest areas on the planet for the mission planners at my office to image with the THEMIS camera. If you've got the Google Earth browser plugin installed, you can also try this out without ever leaving your browser.
If/when the spacecraft takes the picture, we email it to you, and it looks something like this.
Eventually (i.e. when the Google guys get around to it) this will be a feature in the Mars Gallery in Google Earth itself.
Demonstrating the application at JPL's Open House earlier this month: