The Flute and the Duck
Once you have the flute, if you play it in front of the weather vane in Kakariko, the duck will come and help you. He can transport you to many locations. Here they are:
#1 Death Mountain
#2 Witch's Hut
#3 Kakariko Village
#4 Link's Cottage
#5 Warp Tile South of Eastern Palace
#6 Warp Tile in Desert
#7 Swamp Ruins
#8 South of Lake Hylia