Here's a bit more on that upcoming NASA announcement. Still the rumour mills are turning and no one really knows what's going to be said.
It could be arsenic based life on Earth, life on Mars or life on Titan. Who knows? The announcement is at 2.00PM EST which is, I think, 7.00PM GMT???
Here's the Register's take on it. I guess the clue is in the words: "a finding that will impact the search for evidence of extraterrestrial life".