Subscribe & Download is a plugin that allows to distribute files through subscriptions. If people want to download something from your website or from third party websites they must submit their contact details. After submission they receive encrypted temporary download link by e-mail. Very simple workflow. All submitted data is saved in database or can be sent to MailChimp, AWeber, iContact, GetResponse, Campaign Monitor, Mad Mimi and MyMail autoresponders.
Demo: http://codecanyon.net/item/subscribe-download/2687305