(set-language-environment "Japanese")
(set-default-coding-systems 'UTF-8-unix)
(set-terminal-coding-system 'UTF-8-unix)
(set-keyboard-coding-system 'UTF-8-unix)
(setq default-buffer-file-coding-system 'UTF-8-unix)
(require 'un-define) ; UTF-8 サポート(app-xemacs/mule-ucs)
(set-buffer-file-coding-system-for-read 'utf-8)
と書けばいいらしい。