Well that was a good article, but there is another solution worth a try:
Jive Messenger: http://www.jivesoftware.org/messenger/
It is made on java and works great on FreeBSD, Windows and Linux, the installation is 5 seconds, you got a web interface, a lot of settings to play with, and you can use a lot of DB for data storage.
Moving from one server to another is as easy as copy the DB to the new box and reinstall.
And it is open source.
I migrate from Jabberd to this one and i cannot be more happy