here is the Chat Rooms link-
http://neurotalk.psychcentral.com/chat/flashchat.php

it is also up in the blue band or bar {if you use the default theme} on the upper right just to the left of the Log Out.

If you are using the default theme down near the bottom of the main forum topic page { http://neurotalk.psychcentral.com/index.php } there is a section that shows if anyone is in Chat.

for some reason that doesn't show on the other themes.

when u click on the chatroom link it should open up automatically and you should be able to chat with any one that is in there - once in you can use options and other settings to customize if u want to.