A flock of…..
cube sats… obviously! Planet Labs Flock-1 has been in the news quite a bit since it successfully launched its initial 2 cube sats from the International Space Station. These are remarkable little satellites (see the image sequence on the link above at the bottom of the page) that are designed to be small, light, very low cost and replaceable, allowing the provision of relatively high resolution imagery (~4m) of the entire globe at any one time using off-the-shelf components. Each unit is called a Dove and is about the same size as one! Weighing in at only 5kg. But its the IT side which may well be the bigger task - downloading, stitching and distributing a 10 terapixel image of a regular basis is no trivial task!
UPDATE: and hot on the heels, covered over at the BBC and this