Long suspected, but only now proven.
We present direct evidence of feathers in Velociraptor mongoliensis based on the presence of quill knobs on the posterior forearm. In many living birds, raised knobs along the caudal margin of theulnarevealwhere the quills of the secondary feathers are anchored to the bone by follicular ligaments. Quill knobs are variably present in extant bird species and are present in only a few basal taxa such as Ichthyornis (2), so their absence does not necessarily indicate a lack of feathers. Their presence, however, is a direct indicator of feathers of modern aspect (e.g., feathers composed of a rachis and vanes formed by barbs).
The picture is of a mongoliensis and shows feathers roughly where the new study says they are. For information on how the "feathered dinosaur" controversy bears on the debate over AGW, check this out.