The recent discovery of a rocky planet three times the mass of Earth orbiting the red dwarf star Gliese 581 just 20.5 LY away suggests that Earth-like planets may be rather common throughout the galaxy. It was found by a team of planet hunters led by astronomers at the UCSC, and the Carnegie Institution of Washington and principal investigator Dr. Steven Vogt calls the planet "Zarmina's world" after his wife.
As the always interesting Technovelgy has pointed out, the planet is an example of what Issac Asimov called a ribbon world, a planet that is tidally locked with one side of the planet always facing the sun.
It was a ribbon world – of which the Galaxy boasts sufficient, but among which, the inhabited variety is a rarity for the physical requirements are difficult to meet. It was a world, in other words, where the two halves face the monotonous extremes of heat and cold, while the region of possible life is the girdling ribbon of the twilight zone. (Foundation and Empire, 1952)
Dr. Vogt was interviewed about the discovery on Science Friday: A 'Goldilocks' Planet?