We have replaced the somewhat unreliable LJTalk Jabber server with a new one. The new one is based on ejabberd (http://www.ejabberd.im/).
Our expectation is that this will be a much more scalable and reliable solution and the chronic LJTalk downtime will be a thing of the past.
A couple of known issues:
1) All of your LJTalk contacts will probably move to a new livejournal.com group in your client.
2) Some clients might prompt you to accept a new certificate.
Please comment in this thread about your experiences or problems using the new server.