It was exciting enough that the planet Kepler-22B was discovered right around the time that we got to see Frank Drake talk just over a week ago, but today NASA announced the discovery of two new earth-size planets. Kepler-22B has just the right orbit to be a good temperature for life, but they believe it may not be able to support a rocky surface because of its size (about 2.5 times Earth's diameter). The newest planets are more earth-like in size, but they are very close to their sun, so they are unlikely to have water in liquid form. Also, obvious to all of you who know Kepler's laws of motion, if these planets are very close to their sun, they will have very short orbits, so a year there is is between 6 and 20 days here. I just had a birthday, and while I can see that it would be nice to have a lot more birthdays, I'm really glad that I don't live on Kepler-20f because I would be 2872 years old! Since this system is about 1000 light years away, its unlikely that I'll get to visit there anyway.
None of these planets are outstanding candidates for life as we know it on Earth, but its really exciting that the Kepler spacecraft is finding so many interesting planets so quickly. It really is starting to seem quite likely there are many Earth-like planets out there.
Read more about the Kepler-20 star system here.