NASA and it's international partners recently approved a year long stay aboard the ISS for two crew members. How will this and other work going on aboard the station pave the way for humans to follow Curiosity to Mars? This article from NASA's International Space Station page delves into the details.
NASA - How Space Station Can Help Humans Follow Curiosity to Mars and Beyond: "With all of the excitement of the Mars Curiosity landing, many are looking to move from robots to humans for exploration beyond Earth's orbit. Keeping in mind the Seven Minutes of Terror, just imagine the nail-biting moments of putting people into the harsh environment of space far from their home planet. Taking the guess work out of long-duration exploration, however, is one of the benefits of the International Space Station. This orbiting laboratory serves as a test bed for technology and helps researchers understand how to prepare for extended trips in space. "