Fanfiction chats.?

Answer 1

Go to the website of the publishers of the series you are interested in.
Often they have a chat room or a link to a fan site with such.
Or go to the website of the author, and follow links from there.
Lastly, google on the name of the series, add a word like chat.

I can give you one link to a fanfiction site:
http://bar.baen.com/WB/default.asp?boardid=2
As you can see, the first thing it asks is for you to sign in, which I never done, so I can help you further about what is going on there.