WS-BPEL is the standard to define executable business processes in a Web service world. Numerous commercial and open source BPEL engines exist on the market today that allow the execution of process models defined in BPEL. However, these execution engines only provide access to process model and process instance data in terms of proprietary APIs. In this paper we present an approach that models BPEL process models and process instances as resources and thus provides a uniform access scheme for process model and process instance data. This is crucial because access to process model and process instance data is needed in different scenarios that are of key relevance in enterprises today. These scenarios include compliance checking, repair of faulted business processes as well as real-time monitoring of business processes. The lack of a uniform access scheme to process model and process instance data hampers the exchangeability of BPEL engines and therefore results in a potential vendor lock-in.