The invention relates to a method for billing internet transactions via mobile radio telephone service. By using WAP (Wireless Application Protocol), it is possible to select and, optionally, reserve goods and services (information, tickets, CD's, hotel rooms, etc) sold via the internet. When the customer decides to purchase the good or service, he or she conducts a payment transaction from the mobile radio telephone device. According to the invention, the customer data required for conducting a payment transaction is centrally maintained in a database of a payment gateway.