From the ESO website:

On Monday 12 September 2011, astronomers will report significant new results in the field of exoplanets, obtained with the High Accuracy Radial Velocity Planet Searcher, better known as HARPS, the spectrograph on ESO’s 3.6-metre telescope at La Silla Observatory in Chile.

On Monday the 12th at 16:00 CEST an online press conference will take place and a significant announcement will be made. These sorts of announcements are not common so I will admit I am very excited. I only hope that what will be announced is something that will broaden our knowledge about Exoplanets and that it is not just a PR stunt promoting a discovery based upon a mountain of assumptions.

It is hard to say what the announcement will be, but that it might be related to a planet in the habitable zone would be a good guess. Think you know what they will announce? Feel free to present your assumptions in the comment section.