[sahirh]

For XMPP, I recommend checking out Prosody (http://prosody.im). You can get a working system up with Off-the-record instant messaging and internal file transfers in an afternoon, if you're familiar with UNIX system administration.

If you use a client like Jitsi, you can do ZRTP encrypted calls through the server as well. Use your own SSL certificates for SSL.

Ejabberd is also good, however the debug information was pretty inadequate. Also helps to be familiar with erlang.