We're not really sure whether there is currently, or has ever been, life on Mars. Russia is taking a proactive approach to that whole situation and sending a spacecraft 140 million miles or so to visit the red planet with a cargo of microbial sightseers.
Russia is scheduled to launch their Phobos-Grunt mission toward Mars as soon as tomorrow. The primary mission of the spacecraft is to land on Phobos (Mars' biggest moon), scoop up some rocks, and bring them back to Earth by 2014. So that's cool. But along for the ride is a special cargo module from the Planetary Society which contains 30 separate forms of life, including bacteria, other microorganisms, and a few of these:
This is a tardigrade, also known as a water bear. They're microscopic animals (with legs and all) that can reach up to a millimeter in size, and has proven to be spectacularly resilient to heat, cold, dehydration, radiation, the vacuum of space, and pretty much whatever else can be thrown at them. The idea behind this experiment is to see whether it's possible for life (whether it's bacteria or something more complicated) to travel between planets, and if the water bears come back alive, it means that life on Earth could potentially have arrived from Mars, or even beyond.
Or, that's the idea, anyway, but I can already tell you what's going to happen. What's going to happen is that this space probe is gonna crash on Mars, these water bears are going to get loose, they're going to grow to monstrous sizes, they're going to get super-intelligent, they're going to build rocket ships and come back to Earth, and then they're going to star in a Syfy Original Movie. Awesome!