Within each world (server), there are NPCs who issue a string of numbers called World Passes. Giving a World Pass to a friend will let that person create a character in the same world as you. When your friend creates a new character, have him or her enter the name of the server where your character resides and the world pass you gave him and his character will end up on the same world as you.
Update: This guide is no longer relevant since World Passes are no longer needed. You can now select the server you want to start on during character creation.
This quest gives you the Map of the Northlands which covers the areas Beaucedine Glacier and Xarcabard. To start the quest you must make your way to Chateau d'Oraguille and examine Queen Leaute's Grave. After doing so, you must talk to the NPC, Chalvatot, who is standing nearby twice in order to trigger a cut-scene. At the end, he will...