This is the newly described fossil primate Darwinius masillae. Ida (she's a female) lived around 47 million years ago in what's now Europe, and she was more or less an early monkey, or at least an early monkey cousin.
The amazing thing here is the completeness of this fossil. Until the great human expansion, primates have lived mostly in tropical areas, and their bones don't often make it into the fossil record. Here we have not only bones, but the outlines of the body and even the stomach contents.
She doesn't need all the hype that's being tossed around about her: for example, she's not a "missing link"- there's no such thing as a "missing link" in modern evolutionary theory. (For a more complete deconstruction of the over-the-top publiciy she's receiving in some quarters, see sensible science writer Carl Zimmer's article.)
But she's still pretty awesome.