If purchasing a firearm represents a first step in personal protection, learning how to use it is the logical and necessary second step.  As KC writes:

Owning a gun is just the first step on a journey. Guns are not self-protection talismans that ward off evil-doers all by themselves: You have to have it handy when you need it and you need to be ready, willing and able to defend your life and your loved one’s lives, if, God forbid, the need to do so arises.

Where does one start though?  As a relatively new gun owner, I would suggest you give these folks a look.

You can read about it here but I also recommend you bookmark them and regularly visit their site.  They have a lot of good information that focuses on firearms training, personal security, and other preparation-related issues.  I’ve gone shooting with Kevin, Robert, and Jaci so I can personally vouch for their knowledge of firearms-related subjects.  They are good people and are compiling a lot of useful information you can apply.  Check them out, its worth your time.