This addon adds the ability to set a special price and expiry date directly from the product-editor, instead of setting it on specials.php.
This is particularily useful if you have a lot of products, and the dropdown on specials.php is getting annoying.
The specials still show up on specials.php, so you can still easily manage the products you already have on discount.

##For earlier versions##
If you are on a version prior to 1.0.5.9, you can still install this addon, using version 1.1, but you will need to insert a hook-call at admin/categories.php (line 617 on 1.0.5.0):

<?php
echo $OSCOM_Hooks->call('categories', 'injectDataForm');
?>

This call is added in core from 1.0.5.9 and later, so it's fine to add to an earlier version, and will not be overwritten by an update, if you update to at least 1.0.5.9.
The layout might be off, but if you look at the other input-boxes in categories.php, you might be able to figure out how to ammend includes/hooks/admin/categories/productSpecials.php accordingly

To install upload everything beside this file to the coresponding directories at the server.
NOTE! All files go to the includes of the root directory, and not the admin/includes!
Copy and translate the English language-file as needed.

Credit goes to the PhoenixCart core-developers for making it possible to install without modifying core.