This is probably the best website about real self defense that I found.
I try to describe it in short: Most people think martial arts is self defense, while actually it has not much to do with self defense. In a case of self defense, the other person is not trying to fight you, but to kill you or commit some other crime. The crime is a process and a hand to hand fight only comes when everything else has failed, so it is not that common and to really defend yourself, there is a lot more you need to consider, especially legal things.
This could be listed in the tutorials links section, but I thought it is more about knowing things, then it is about doing, of course the author also provides phsyical training advice. So if you want to become a fighter you probably should read this website first, before you do something stupid or waste your time with useless martial arts, that will fail you in a real situation.