Since the landing of "The Curiosity," Mars imaginings may be a thing of the past! The photos of planet are coming through and there doesn't appear to be any little creatures.
There's a long history of fictional musings on the interaction between Earthlings and Martians, including films. Here's one of my favorite "human" encounters with Martians:
Look for these feature length films in our DVD collection:
Doom [DVD DOO]
Mars Attacks! [DVD MAR]
Mars Needs Moms [J DVD MAR]
Popeye, the Sailor. 1933-1938 [DVD POP] This set contains a Fleischer Studio short, "A trip to Mars" (1924).