Colonizing the moon would lead to many advances in space technology. A moon station would also serve as a stepping stone on the way to Mars. If we could achieve the technology and expertise to colonize the moon, we would be well on our way to reaching Mars and beyond.
Colonizing the moon would indeed aid any future Mars mission, mostly because much of the knowledge and experience from such an endeavor would also be applicable to landing and surviving on Mars. It would also draw more attention to space and space exploration thus increasing public support and determination for a Mars mission.