On: Mars rover camera project manager explains 2MP cam...

[brudgers]

It appears that NASA already sent a microphone to Mars.

And you can listen to it:

http://mars.jpl.nasa.gov/msp98/lidar/microphone/mic_found.ht...

[Edit] Never mind, Mars Polar Lander crashed.

http://en.wikipedia.org/wiki/Mars_Polar_Lander#Communication...

[InclinedPlane → brudgers]

NASA sent microphones to Mars twice, but neither were used due to technical reasons (one because the vehicle crashed).