XML has become the standard platform for structured data exchange on the Web. Next concern of semantic Web is the exchange of rules in markup language form. The rules should be represented in such a way as to allow software agents to process and browse them for human comprehension. For this purpose, we propose a language eXtensible Rule Markup Language (XRML). XRML is composed of rule identification, rule structure, and rule triggering markup languages. In XRML, a critical concern is how to extract the structured rules implicitly embedded in the Web pages and keep consistency between the two. By using the XRML, the Web based knowledge management systems (KMS) can be integrated with rule-based expert systems. The advanced architecture with XRML can extend the application of KMS to automated form processing, preventive auditing, rule exchange and integration, and agent-based e-commerce.