GetSimple has an SVN setup over on Google Code. You have the ability to automatically pull down the latest SVN copy with the script below.

Download and install PHPSVNClient and upload it to your server. Make sure you change the include_once line below to match the new path of where you installed it.

Create svn.php, copy in the code below, and upload it to another directory on your server.

<?php
/*
 Pulls a new GetSimple installation directly from the GetSimple SVN
 
 The paths don't need to be 'absolute', but I have them this way because my host required absolute paths for cron jobs.
 
*/

# setup
ignore_user_abort(true);
set_time_limit(0);
include_once('/absolute/path/to/scripts/svnpull/phpsvnclient.php');

echo "[".date('r')."] Started";

# create new instance of svn client
$svnurl = 'http://get-simple-cms.googlecode.com/svn/';
$phpsvnclient = new phpsvnclient($svnurl);
	
# rename old admin directory
rename('/absolute/path/to/getsimple/', '/absolute/path/to/getsimple-old/');
	
# create new admin directory
mkdir('/absolute/path/to/getsimple/');

echo "[".date('r')."] Copying...";
	
# pull new admin directory. 
$phpsvnclient->checkOut('trunk/', '/absolute/path/to/getsimple/');

echo "[".date('r')."] Completed";

?>

1. I have the script using absolute paths. This isn't necessary, but for my host, any cron jobs need to use absolute paths.
2. You can check out any parts of GetSimple with this script. Variations:

Checkout only the new /admin/ directory

$phpsvnclient->checkOut('trunk/admin/', '/absolute/path/to/getsimple/admin/');

Checkout a specific version (not beta):

$phpsvnclient->checkOut('tags/3.0/', '/absolute/path/to/getsimple/');