Hi Sean,
There's no setting in the system currently that allows you to reverse the order of items. But, you can hack the public theme to do this.
If you want the items to display in reverse order, you'll need to use a PHP function called array_reverse() to reverse the array of items fed to the items/browse.php file. So, right above where you see:
<?php foreach($items as $item): ?>
You need to add:
<?php $items = array_reverse($items); ?>
So, the final change should look like this:
<?php foreach($items as $item): ?>
<?php $items = array_reverse($items); ?>
This essentially redefines the $items array on that page to display in reverse order.
array_reverse() is documented at PHP.net.