Microfossils of sulphur-metabolizing cells in 3.4-billion-year-old rocks of Western Australia; Nature Geoscience Aug 21.
“Sulphur isotope data from early Archaean rocks suggest that microbes with metabolisms based on sulphur existed almost 3.5 billion years ago, leading to suggestions that the earliest microbial ecosystems were sulphur-based. However, morphological evidence for these sulphur-metabolizing bacteria has been elusive. Here we report the presence of microstructures from the 3.4-billion-year-old Strelley Pool Formation in Western Australia that are associated with micrometre-sized pyrite crystals. The microstructures we identify exhibit indicators of biological affinity, including hollow cell lumens, carbonaceous cell walls enriched in nitrogen….”
(…meant that the text got too technical for me at this point!). For a quick layperson’s view, see the blog by the nice folk at ZME Science.
Note to creationists on G+, I’ll see your 6000 yrs and raise you 3.5 billion!
madame scientist's not-so-mad musings 
It seems as if almost every discovery in the last dozen years – here on Earth and elsewhere – has made life more and more likely to be widely distributed in the Universe. I worry, though, that we haven’t observed a single body other than Earth with a non-equilibrium atmosphere, except (maybe) Titan.
Dear Bill, could you explain non-equilibrium atmosphere. Do you mean an atmosphere supporting life as we know it? Or dense atmosphere like the earth’s. Thanks!
Rajini Rao From as far away as you could see anything about Earth’s atmosphere, you’d know that something very, very odd was going on here. Our atmosphere is nowhere near chemical equilibrium, especially all that loose, reactive oxygen.
Likely, any planet that harbored life would show some signature of disequilibrium. Titan shows chemical oddnesses that may represent the activities of methanogenic life. Mars’ atmosphere seems ‘dead’ – in lifeless equilibrium – except, maybe for some quirky isotopic ratios, so if there’s life there, it’s rare or inactive.