jBilling is a web-based enterprise billing and rating system. It manages your subscribers with automatic invoicing (email and PDF) and payment processing (credit cards, checks, direct deposit). Robust, well documented and easy to use!
Open source project that offer summary and download services on this page is a project that carry out their development work on other open source development sites. Their work is linked to this page via a feature called OFI, and their work is not carried out here on OSDN site.
