Planet 51 (2009)

PLANET 51 is a galactic-sized alien adventure comedy about Earth astronaut Captain Charles "Chuck" Baker who lands on Planet 51 thinking he's the first to set foot on it. To his surprise he discovers that it's inhabited by little green people with antennae who live on a white picket fenced world reminiscent of a cheerfully innocent 1950's America, and whose only fear is that they will be over-run by alien invaders…Like Chuck. With the help of a friendly teenager, Lem, and his friends, Chuck tries to get back safely to his spaceship and return home before he's captured.

Official website: http://www.planet51.com/