Says the ESA:

Open invitation for image feedback:: You can assist the Mars Express team with additional processing of the raw image data files as well as interpretation: What do you see? What part of the Mars surface is being shown? Can you identify any geographical features? What regions of the atmosphere or atmospheric components do you see?

Keep in mind these images are what they're calling "tourist quality" (i.e. non-scientific), so they aren't going to be used in any major studies or experiments anytime soon. They are, however, perfect for Mars enthusiasts and weather-watchers. And who knows, maybe you'll be lucky enough to use this web cam to spot a careless Martian doing something they can't take back. Interstellar YouTube video? WIN. [ESA via Discover Magazine]

Says NASA, via its Jet Propulsion Laboratory web page:

If Mars had an on-line Web site for ads, one of them might say something like this: "Wanted: Gentle space-age dust removal system to clean solar cells without leaving grit behind. Please direct inquiries to NASA."

NASA's Spirit rover has accumulated a lot of dust during four years of exploring Mars, especially following last year's dust storms. Only about one-third of incoming sunlight is able to penetrate dust on the rover's solar panels to be converted to electricity. As a result, Spirit is experiencing the lowest energy levels to date and accumulating a backlog of data waiting to be transmitted to Earth. The only available cleaning agent would be a timely gust of Martian wind!