API for electronic funds transfer

I need to periodically transfer money to my user's bank account. I don't want to force my users to have a Paypal account or any similar service, so I prefer a simple transfer using an IBAN user, just like Google Adsense pays its publishers.

Hopefully I will have many users soon, so I will be doing a lot of translations (thousands initially, hopefully going to millions), so I will need to automate this with a web service to do translations.

I have searched around and my question is, what services are available to do something like this that work all over the world (or at least in Europe and the US)? Dwolla only works in the USA. It is not clear to me if Paypal or Amazon Payments can offer this type of service.