Recently, I have discovered a hidden Nether Portal in Minecaft: Xbox 360! To get there, you must go to the tutorial from the menu where you make a new map. From there, you will need to go under the giant, floating "Minecraft" symbol. Then, you make a tower or stairs up to it. Go around the Symbol until you see a switch. Flip the switch, and a piece of the symbol should slide up. go in, an in there you will find a Nether Portal! it functions just like any other portal would. Enjoy!
http://www.minecraftforum.net/topic/1353970-tutorial-world-secrets/
http://www.minecraftforum.net/topic/1223658-easter-eggs-in-tutorial-map/
http://www.minecraftforum.net/topic/1351608-minecraft-signeaster-egg/
http://www.minecraftforum.net/topic/1353296-new-stuff-in-tutorial-world/