The Back In Time glitch (BiT) is a bizarre trick that allows you to respawn on the title screen map.
When done correctly, you will respawn in the title screen map (a stripped down version of Eldin Bridge that lacks loading triggers). Pressing start will cause the title screen logo to pop open, and on the Wii version pressing other buttons will sometimes crash the game. If you jump into the void, you will gain normal control of Link. You can save here to create the Back in Time Game File. If you get Gameover and continue, you'll respawn at the first King Bublin fight. Unfortunately, due to the Back in Time Save effect, Kakariko will be covered in Twilight after you beat King Bublin, and due to the fact that you are totally itemless, it's impossible to continue the game.
If you do the Back in Time Glitch at the very beginning of the game and save, you can save about five minutes. See Back in Time Save page for more information.
There is a consistent set-up for BiT at Ordon Bridge which involves pressing D-right and A at the same time which uses the map to buffer.
1) Hang off the edge shown in the video between the two ropes
2) Press D-Right and A at the same time (alternatively you can unplug your controller, hold D-right and A then plug it back in, this assures they are both pressed on the same frame)
3) You will see Link drop a frame and the map come up, zoom out once so next time you press B it will cancel the map
4) Soft Reset by pressing Start+X+B (making sure B was pressed last)