Lots of people have firearms, and many of them claim they are for defensive purposes.  Unfortunately, most people lack either the everyday use experience, or the actual training, necessary to use firearms in any effective capacity.  However, there are many professional firearms training schools around the country that can provide training and knowledge.  Most of these are high quality, and are often used by the military and law enforcement, but they also serve civilians!  Many also travel the country, providing classes near you.

This in not an exhaustive list, but merely a small representation of the most popular providers in the country.  Most courses cost between $500-1500 (plus travel, ammo, and expenses).  Most schools also offer DVD-based courses, for around $50.

That's "the cool stuff", but don't forget that the NRA offers more basic courses too.