We'll start off with a little extraterrestrial chemistry. As many will have heard, there are all sorts of hints being dropped that the sample analyzing equipment on the Mars Curiosity rover has detected something very interesting. We'll have to wait until the first week of December to find out what it is, but my money is on polycyclic aromatic hydrocarbons or something other complex abiotic organics.
Here's a detailed look at the issue. The Martian surface has a pretty vigorous amount of perchlorate in it, which was not realized for a long time (and rather complicates the interpretation of some of the past experiments on it). But Curiosity's analytical suite was designed to deal with this, and my guess is that these techniques have worked and that organic material has been detected.
I would very much bet against any sort of strong signature of life-as-we-know-it, though. For one thing, finding that in a random sand dune would seem pretty unlikely. Actually, finding good traces anywhere in the top layer of Martian rock and dust seems unlikely (as opposed to deeper underground, where I'm willing to speculate freely on the possible existence/persistence of bacteria and such). And I'm not sure the Curiosity would be well equipped to discriminate abiotic versus biotic compounds, anyway.
But organic compounds in general, absolutely. This brings up an interestingly false idea that underlies a lot of casual thinking about Mars (and space in general). Many people have this mental picture of everywhere outside Earth being sort of like the surface of our moon. It leads to a false dichotomy: here we have temperate air, liquid water, life and the byproducts of life (oil and coal, for example). Out there is all cold barren rock directly exposed to vacuum and hard radiation. We associate "space" with clean, barren, surfaces and knife-edge shadows, whereas "down here" it's all wet and messy. Not so.
There's plenty of irradiated rock, true, but there's water all over the outer solar system, in huge amounts. And while what we see out there is frozen, it's a near-certainty that there are massive oceans of the liquid stuff down under the various crusts of the larger outer-planet moons. All those alien-invasion movies, the ones with the extraterrestrials after our planet's water, are fun but ridiculous examples of that false dichotomy in action. There's plenty of organic chemistry, too - I've written before about how the colors of Jupiter's clouds remind me of reaction byproducts, and it's no coincidence that they do. The gas giant planets are absolutely full of organic chemicals of all varieties, and they're getting heated, pressurized, mixed, irradiated, and zapped by huge lightning storms all the hours of their days. What isn't in there?
Everything came that way. The solar system has plenty of hydrocarbons, plenty of small carbohydrates, and plenty of amines and other nitrogen-containing compounds in it. The carbonaceous chrondrites are physical evidence that's fallen to Earth - some of these have clearly never been heated since their formation (since they're full of water and volatile organics), so the universe would seem to be awash in small-molecule gorp. There's another false dichotomy, that the materials for life are very rare and precious and only found down here on Earth. But they're everywhere.