I doubt it'll be a planet "simply" capable of supporting life, pretty much any can do that (it just won't be life 'as we know it (Jim)'. If it's a planet it'll be more news of an "Earth Like" planet in the green zone, capable of supporting liquid water and life that metabolises using oxygen. I'm thinking the press conferance will be about a new rover or mabey a new peice of equipment for a rover capable of analysing soil for individual bacteria scale aliens.
Though on the plus side, if it IS aliens, they're probably sentient. Think about it: we havn't sent out any space flights for a while, so if we had the technology to find alien bacteria with the probes already out there we'd have done so by now. Better technology is still here on Earth, unlaunched. Ergo, any aliens we just found would have had to have responded to radio broadcasts! Mabey traveling here by hyperspace!
But yeah, rover. But hyperspace! But rover.