~/.emacs

(setq package-archives '(("gnu" . "http://elpa.gnu.org/packages/")
                         ("marmalade" . "http://marmalade-repo.org/packages/")
                         ("melpa" . "http://melpa.milkbox.net/packages/")))
(require 'package)
(add-to-list 'package-archives
  '("geiser" . "http://download.savannah.gnu.org/releases/geiser/packages"))
(package-initialize)