With the progress of Web-based learning technologies, standardized digital repositories and learning management systems are becoming prevalent over time. The heterogeneity in underlying databases and access methods, however, makes it difficult to share and exchange the learning resources between them. In this paper, we propose an architecture for the search and delivery of learning resources. Based on the SOAP transmission protocol, the architecture seeks to improve interoperability between heterogeneous E-Learning implementations. We also present a general-purpose query language as a building block of the architecture. The language provides a unified query interface for resource repositories, thereby shielding the users from the differences in underlying databases and metadata schemas. To highlight our design, an implementation using LOM, native XML database and XPath is presented. The last part of this paper discusses technical and pedagogical issues of concern regarding the launching of contents from within standardized LMSs.