Emperor Palpatine used the Dark Side to transfer his consciousness into a series of clone bodies.
Yoda's unnamed tridactyl species just lives a long time.
I think that the only reason Jedi* might live longer is because they lead healthier, more active lifestyles that promote good health and physical fitness into advanced age. Maybe being more in-tune with the force adds a few more years what with control over one's body processes, but by and large, Jedi have the same lifespan as any other member of their species.
*The notion of a Sith worth the title living to old age is... unlikely That would indicate that you're being careful and taking it easy and not Seizing Power by Gaining Strength through Passion
