To use navi2ch, put the following into ~/.emacs.

(require 'navi2ch)

To use monafonts with Xemacs, put

(require 'navi2ch-mona)
(add-hook 'navi2ch-article-arrange-message-hook
           'navi2ch-mona-arrange-message)

into ~/.xemacs and set board name to be viewed with monafonts.

(setq navi2ch-mona-enable-board-list '("mona" "prog"))