Great news, the new version of Paypal Subscriptions for 6.x has been released! This version adds the following:

New Features:

-New hook_process_ipn() function which allows developers to hook the ipn function from within their own modules!

-Page Style options for Paypal on a per-subscriptions basis. Use your site style on your Paypal pages!

-Added the t() function to menu items and descriptions for internationalization and translation compatibility