People have been curious about the Entralink and what it does. I've done some playing around, and I've figured it (mostly) out. Basically, if you are between Route 4 (the Sandstorm route) and Route 10 (Victory Road entrance) and you have your C-Gear on, you can be connected to via the Entralink. You do not need to do anything special to have a friend join your world via the Entralink, only have your C-Gear on, be nearby them physically with your DS, and be in this area of Unova. They will join your world using their multiplayer avatar (what you would see in the Union Room), unless they are doing certain select things that turn them temporarily into a Pokemon. You can tell which thing running around is your friend by being able to walk through them. Your friend, using the Entralink, can complete "Missions", little sidequests that involve things like challenging you to a Flat Battle, hiding an item somewhere, or simply convincing you to talk to them ingame. By completing these, they earn "Pass Orbs", orbs that can be used (anytime!) to activate powers similar to the ones they give you, but on a smaller scale. They can find what missions are available in your world by talking to your "Entree", the tiny thing in the very center of the main area of your Entralink. By doing missions, your Entree can level up, giving you access to better missions and better powers. Some of these "Missions" involve turning into a Pokemon and convincing you to talk to them. Once you do, they will give you powers such as: Halving the number of steps to hatch an egg for 30 minutes Doubling experience gained from battle for 30 minutes Doubling money earned from battle for 30 minutes Obviously, if you see a Pokemon running around that does NOT belong in Unova (Machop, Meowth, Geodude), talk to it. Your friend can also do things like hide an item somewhere for you to find later or heal your lead Pokemon to full health mid-battle, if they select the appropriate mission. By doing these, again, they earn "Pass Orbs", which they can spend in the Singleplayer mode to grant similar powers (half the number of steps to hatch eggs, double experience, double money, etc.) to themselves for 3 minutes at a time. Via using the Entralink in conjunction with an Amulet Coin, one could theoretically earn 4x the amount of money as normal when challenging the Elite Four. I'm still playing around with it; I haven't had a chance to find out about Black City or White Forest yet. However, when I do figure these out, I'll update this guide.