Hacked again

Three of my domains were hacked Friday night. The hacker was very good at what he does as he inserted HTML code into the normal code of the page. The code he inserted brought pop-up windows with advertising. I would guess if someone clicked on the pop-up he would get paid a few cents. The code was very hard to find and remove so I decided to just overwrite the index files from my backups. A real pain in the butt taking about an hour to fix the damage he caused. Now I ask you, what kind of a jerk hacks into a funeral home page ?