Here is a sample configuration you could want to add to your .emacs:

(load-library "zenirc")

(eval-after-load "zenirc"
    '(progn
     (load "zenirc-chanbuf.elc")
     (add-hook 'zenirc-mode-hook  'zenirc-chanbuf-minor-mode)))

(setq zenirc-server-alist
    '(("IRCSERVER" IRCPORT SERVERPASS "NICK" nil)))