FYI, Astronomes have found over 300 exo planets; that are planets outside our solar system, orbiting other stars. However, all have been gas planets. Gas planets are like our four outer planets in our solar system; namely Jupiter, Saturn, Uranus and Neptune. 

Just a few days ago, it was announced that the first rocky planet was found. You can read more about it here.

http://www.usatoday.com/tech/science/space/2009-09-16-rocky-planet_N.htm