Before studying the particulars of solar flares, it's important to know the basics of the sun. The following links will provide you with background in solar science. From the Yohkoh Mission Public Outreach Project. In particular, check out the Solar Tour and Structure of the Sun . A more advanced and detailed look at many aspects of solar science.
Sunspots are the most easily observed solar feature, and a useful subject for classroom study.
If you become enthusiastic about sunspot observation, join our SunspotNet collaborative online activity. The energy for solar flares and other energetic events on and in the sun comes from the sun's magnetic field. Follow these links to learn more about this subject.