Serving the greater good can be accomplished in many ways. And most don't require setting up an IRS approved nonprofit, a risky endeavor in this economic environment, and always a complicated task that many people underestimate.
If you are thinking of starting a new nonprofit, you might want to put it off until the economic future becomes clear. Better yet, consider one of the many other ways of applying your passion for a cause such as:
2. Volunteer.Volunteer for a nonprofit that is doing something similar to what you have in mind. Consider joining that group's board, or even taking a job there. Even if you later decide to start your own group, the experience with an existing nonprofit will help you hone your ideas and learn what is realistic rather than just idealistic.
Become a social entrepreneur by forming a for-profit social venture to accomplish your social goals; or set up a small business with the goal of contributing some or all profits to a charitable cause.
A traditional nonprofit is not the only business structure that can be set up to do good. See the alternatives in Before Starting a Nonprofit, Consider Other Business Structures.