Default window splitting

[Philippe Combes]

Hi all,

When I run
# emacs file1 file2
then emacs splits the window horizontally, with file1 displayed above file2.
I would like to change this defaut behaviour to let emacs split the 
window VERTICALLY, so that the files appear side-by-side.

So far, I always use C-x 1, C-x 3, C-x b <Enter> to get file2 on the 
left, and file1 on the right. I would like to avoid typing three 
commands every time I launch emacs on several files...

Any suggestion welcome...
Thanks in advance,

Philippe