Business processes are established via relationships between partners with a common goal. These relationships are specified in contracts, which could be explicit or implicit, oral or written, and so on. When a person searches for a business partner, she is looking for a partner that can fulfill a relationship specified in a contract. To support such processes in the Internet (and in the Web) it is necessary to characterize all of its aspects, such as agents, contracts, roles, relationships, interactions between partners, policies, etc. This dissertation presents the Contract Oriented Web Services Model (COWS) - a model for an appropriate environment for E-Business dialogues, implemented using Web Services. COWS is based on well-defined contracts agreed upon by all concerned parties and incorporates various levels of applicable policies. These policies can be related to payment methods, quality of service (QoS), privacy policies, rights, products return, trust, etc. Contracts may refer to other contracts and are valid within forae, which have default global policies. A prototype web environment supporting COWS has been implemented to test the concepts that extend the discovery process. All COWS models have been specified as ontologies, using Flora-2.