A good start to achieving your admirable goal is to research the requirements and create a Resume that meets and/or exceeds these requirements. Some good information about requiremetns is found in the FAQ on the Peace Corp site.
Do I need a college degree?
Opportunities are available for individuals with a combination of relative job experience and education, though most opportunities require a four-year degree.
Do I need to speak a foreign language?
Language requirements vary by job opportunity, and any requirements will be listed in the job opening. Search the Volunteer Openings page for specific requirements.
There are also many other alternative service sites that may help you prepare for the extended service in the Peace corp.
Peace Corp Alternatives:
Cross Cultural Solutions
International Volunteer HQ