I think that menu bar thingy (system message) is going to be removed from permanent display, and only appear when there are actual important system messages, as otherwise people just tend to ignore it.
I think once per site chat rolls out, there will be a 'chat' link up next to 'meta'/'parent'. Until then the only link is in the chatroom faq post, but this should be featured on the main site in the new featured meta posts bit on the right.