Can you visit the city with a friend in Animal Crossing City Folk?

(1) You and your friend must have internet access.

(2) You need to acquire your "friend code" from the guard dog (one on the right) in front of your city gate. (Note: If you've just started the game up, I don't think it will assign this to you until you've established which house you live in and talked to everyone in your town, gotten set up at the bank, etc....)

(3) Once you get your friend code, you need to call or email your friend and tell them your friend code, player name, and the name of your city and record their information as well.

(4) On the bottom of your screen (where you access your 'pockets', and 'designs') there is a little heart icon. Click on that icon and select the option 'register a friend' and it'll prompt you for those three pieces of information you recorded and give you a place to add comments.

(5) Once your friend registers your code in their system as well (both of you need to register each other) a hollow heart will appear next to their name in your registry. From there, you can go to your guard dog and select the option "I want to go out!". He will ask you by what method (wifi or ds suitcase).

(6) He will then provide you a list of available cities you can visit, and if your friend is active and has their gate open then they will be listed. Click on your friend and the game will automatically connect you to their city - a video will play of you running through the gate of your city and then coming out of a similar gate into theirs.

(7) Once you successfully visit your friend's city (and if you have your console options set to accept it) then a filled-in heart will appear next to their name in your registry and this signifies that you can now send them letters from your town hall.