What would life on planet Gliese 581 C or D (the most earth-like planets discovered in 2005 or so) look like?

They discovered this planet but its to far for human piloted spaceships to reach and report back so no expeditions are set yet, but im curious on what people would think whats on it, are their people (Humans) like us on it? Maybe a new species of human evolved on it? or maybe it has no intelligence and is a 3rd world planet that was/is like the prehistoric age with the wild living wild and no humanoid disturbance or interferance?