Ok, to start off, do your usual run, and get up to the point in Hyrule Castle where you meet Zelda in the prison cell in the beginning of the game. Leave the room and enter the big room with a lot of guards. Walk to any spot in here where you can jump off the ledge. While in mid-air, press SELECT to save your game and exit.

     Once you re-enter your save file, you will be in Zelda's prison cell... A guard nearby will have a giant mace ball. While standing inside the prison cell, let the guard hit you with the mace and walk into the wall on the right during your invincibility frames.

     Once inside the wall, you'll be invisible, so maneuvering around is kind of trick. Be warned; if you walk near the edge of the wall, you will jump out into the normal sections of the castle floors, meaning you'll have to redo the glitch. From where the prison cell was, you'll mostly want to go north, and after some time, you will be inside Ganon's chamber, where the final boss is. Just walk past him into the chamber holding the triforce and BOOM! You have beaten A Link to the Past in about 5 minutes! Have fun!

     Since my wording wasn't the best, here is a link to a Youtube video, just in case you need a visual guide.
          Link to the Video: http://youtu.be/1bjYuzDqhHU
     BTW, don't be concerned, this glitch is VERY easy to perform...

But that would be sort of wasteful,
How would I be able to enjoy the story if I skipped to the end? :L

Honestly if your going for a speed-run you wouldn't use this method because It was cheating so I don't see why you would ever use it besides to try it.

Nice find anyway.

SpeedIsMyName : I would like to know if you learned of that from some one else? If not how in the world did your figure out you could do that. That would have to be some of the most random series of events to happen sequentially. When you re enter your save file does it give you an option where to start? Inside links house? If you go out into the room where Gannon does it start a battle? You would not have the master sword of the silver arrows to fight him. I Just cant fathom that any person could or would do any or all of the actions for this cheat but that's why they are called cheats so you can cheat ha.    

xXCHUCKXx86 : I'd have to be bored out of my mind to find this on my own, but yes, I found this on the Internet, and technically, doing this is not cheating, it's more an abuse of faulty programming in that certain wall I mentioned. It'd only be cheating If I used a cheating device like a Game Genie to win the game. As long as it's within the game's programming and nothing else, it's veritable...