JPL Solar System Ambassador program is for volunteers (non-NASA employees) who wish to be involved in educational and community outreach related to space exploration. Provided materials (mostly web-based) and telephone briefings tend to be mostly related to JPL programs, but ambassadors are free to define their own presentation subjects and styles. I've been in this program since 2007, and I have really enjoyed doing presentations at schools, libraries, museums, and scouting events. I personally tend to use a lot of simulation software (especially Orbiter and Stellarium) in my presentations, which is purely my choice based on my interests and skills. Other ambassadors may focus more on PowerPoint, video, hands-on activities, and sky observations.
If you live in the United States and are interested in becoming a JPL Solar System Ambassador, September is the only time you can apply, so act now! You certainly don't have to be an engineer, scientist, or teacher, though many ambassadors do have such backgrounds (many are also amateur astronomers). The main thing is that you have an active interest in space exploration and that you enjoy sharing your interests with other people, often but not always children.