Handgun training, where do i start?

I have become interested in home defense, I realize a dog is useful, good security is useful, as well as lighting that illuminates all the "nooks and crannies" around the house. However, of course, a gun is necessary and I have no training in that area. Besides the random 20-30 rounds fired from a sawed off shotgun or a 44 mag when i was a kid for kicks. Where do i start to tackle this problem of lack of knowledge about guns and relative inexperience handling one?