When you deliver the parcel to your friend, he finds two maps in it and gives one to you.
Chat with our AI personalities
same as diamond/pearl
Follow the directions in these pictures: http://bulbapedia.bulbagarden.net/wiki/Turnback_Cave it worked for me in the diamond and pearl games and even in platinum. Good Luck ;)
No. however, if you leave your door open and someone finds it, they can come in to steal your flag.
for diamond, pearl and platinum, when you have gained access to the boat at snow point city, ride on it, to get to the second island in the top right of the map, and progress to Stark mountain, Heatran will be waiting, just remember to save right before you battle him
There is a map of Mt. Coronet in the Sinnoh region.