The first piece of music, which starts five seconds in, and ends at 0:26, is "One Bourbon, One Scotch, One Beer" by George Thorogood and The Destroyers. The second piece of music, which starts at 1:31 and plays on and off until the trailer ends, is "Spaceman" by The Killers.

Planet 51
Trailer
(2:23)

The second piece of music is "Spaceman" by The Killers. I'm not sure about the first.

Planet 51
Trailer
(2:23)

Planet 51
Trailer
(2:23)

Planet 51
Teaser Trailer
(1:50)