Dwolla is an extremely innovative Payment API and the site allows you to transfer money with one of the least payment charges. We have covered Dwolla before here. Here is an interview with Michael Schonfeld, Developer Evangelist of Dwolla API.
PayPal has launched the much anticipated Webhooks support for its Payouts functionality. This allows users to receive notifications on their Webhook URLs for PayPal Payouts transactions. These notifications are currently for status scenarios such as processing, success and denied.