I just configured Adium as my cXMPP chat client on my OS X laptop. Funny that Adium was not mentioned since its mascot is also a duck. a simple bang syntax search on DDG for
will take you to the MU search results for it.
Just chose the XMPP (jabber) from Adium’s Preferences>Account>+ (pulldown]
type in your firstname.lastname@example.org & password
and in a few seconds it connects.
BTW, Adium is free software (not even ad-ware), and I make no money for posting any of this, I just really like the software, especially the UI customizations and themes you can do on it.