Review this page to see the variety of jobs possible with a public administration degree: http://whatcanidowiththismajor.com/major/public-administration/
The CSUSB Career Center http://career.csusb.edu/
An excellent site for careers in public service is: Public Service Careers.org
The primary federal jobs site is: USAJobs "Working for America"
Good sites for local government jobs include:
ICMA JobCenter Leaders at the Core of Better Communities
11 Mistakes to avoid during your federal job search: LINK