The Sun is our star. Here’s a nice introduction from Dr. Plait.It’s a rather typical star, actually. When compared to the Earth, we see that a star is an entirely different type of object from a planet. It is a huge sphere of hydrogen and helium gas almost one and one half million km in diameter. It is a fairly typical star, about average in all respects. Its spectral type is G2V; that puts it right in the middle of the H-R diagram. The visible surface of the Sun shows indications of massive stormswhich release energy into space and toward the Earth. We have a spacecraft called SOHOthat regularly monitors the Sun's weather. With a properly filtered telescope, we can see a variety of features on its surface. This NASA video shows the Sun in an entirely different light, quite literally.Since we believe the Sun to be a rather typical star, we can make some assumptions of the physical details of most other stars. For instance, we are certain that other stars have ‘starspots’. We see other featureson the surface of our star which must be similar to those seen on other stars.Here is an excellent documentary on the Sun from the Discovery Channel.