I got jabber running on my test server.  I've had trouble getting the SSL support going, but its on the way (netstat -ar shows jabberd listening on port 5223 and openssl successfully retrieves the cert from jabberd).  The abundance of clients is good.  With SSL, my security concerns are slackened and it logs on the server and client sides.  Not bad.   This may be the right IM tool for the enterprise.