Add the following lines to your .emacs file. The last three lines define global keys for the commands org-store-link, org-agenda, and org-iswitchb - please choose suitable keys yourself.
;; The following lines are always needed. Choose your own keys.
(add-to-list 'auto-mode-alist '("\\.org\\'" . org-mode))
(global-set-key "\C-cl" 'org-store-link)
(global-set-key "\C-ca" 'org-agenda)
(global-set-key "\C-cb" 'org-iswitchb)
Furthermore, you must activate font-lock-mode in Org
buffers, because significant functionality depends on font-locking being
active. You can do this with either one of the following two lines
(XEmacs user must use the second option):
(global-font-lock-mode 1) ; for all buffers
(add-hook 'org-mode-hook 'turn-on-font-lock) ; Org buffers only
With this setup, all files with extension ‘.org’ will be put into Org mode. As an alternative, make the first line of a file look like this:
MY PROJECTS -*- mode: org; -*-
which will select Org mode for this buffer no matter what
the file's name is. See also the variable
org-insert-mode-line-in-empty-file.
Many commands in Org work on the region is he region is active. To make use
of this, you need to have transient-mark-mode (zmacs-regions in
XEmacs) turned on. In Emacs 23 this is the default, in Emacs 22 you need to
do this yourself with
(transient-mark-mode 1)