Want to upload free ebooks on ibookstore

Does anyone know if it is possible to upload free ebooks on ibookstore? As I know for people that live outside of the states like me, I am not allowed to work directly with Apple on uploading/selling the ebooks to iBooks instead we have to do this through approved aggregators. But I come to think which aggregators would want to do this for selling free books? Can anyone recommend an aggregator that would do this?

Thanks and appreciate it!