A few days ago ESA's Venus express probe completed its first two years orbiting our sister planet. Since then it has been revising and updating our knowledge of the planet, having already returned to us over 1200 Gig of data.
Among the most recent discoveries is the presence of the molecule Hydroxyl in the Venusian atmosphere. The molecule was detected by the Visible and Infrared Thermal Imaging Spectrometer about the craft at an altitude of around 100km from the planet's surface.
This is significant as it is highly reactive stuff, playing many important roles in the relative abundance of substances such as Ozone in atmospheres.
Full story on the ESA site.