The following might be of interest:

*** Vertical Split window
Splits screen vertically if the width of the window is large enough.
Inspired by the following post:
-
http://stackoverflow.com/questions/2081577/setting-emacs-split-to-horizontal

#+begin_src emacs-lisp :tangle yes
  (setq split-height-threshold nil)
  (setq split-width-threshold 160)
#+end_src


Regards
Gustav

On Mon, Oct 17, 2011 at 11:12 AM, Johan Ekh <ekh.johan@gmail.com> wrote:

> Hi all,
> when I use "C-c a a" to create an agenda, my emacs window is split
> horizontally and the agenda is shown in the lower
> window. I'd rather have my emacs window splitted vertically and the agenda
> shown in the right window. How can I do this?
>
> Best regards,
> Johan
>