services is more and more stressed by researchers and practitioners in e-Government, Base Registries, as fully electronic, centralized repositories of information for classes of entities, pose as an infrastructure that can support aggregate electronic services delivery. In the presented approach, a Base Registry storing the citizen records is designed to integrate the legacy databases of 1,034 municipalities and is opened up to support the provision of electronic services towards governmental organizations. Discussion on the results is targeting at best practice examples that can be drawn at scientific and organizational level, but also at the key difficulties that have to be tackled in such public sector information reuse approaches – in relevance with the administrations and industry readiness in each country, in order to fulfill one of the principal conditions for pan-European Public Services.

for interoperability levels of public sector organisations and systems is emerging as an important research challenge in interoperability for governments and administrations. The Government Interoperability Maturity Matrix (GIMM) that is proposed in this paper aims to provide administrations with a simple, self-evaluation method that can be used to assess the current status of the administrations concerning eGovernment interoperability and the steps that need to be taken to improve their positioning in respect to system implementation and services provision to citizens and businesses. The paper expands the three types of interoperability considered in the European Interoperability Framework (EIF) identifying several Interoperability Attributes that need to be taken into consideration in order to evaluate each organisation positioning in eGovernment interoperability and presents the rational of the Methodology that has been formulated and introduced. Within this modeling context, levels of existing interoperability status of organisations are clearly defined, while certain practices or directions lead to interoperability state changes within the maturity matrix.

most active point of transactions between the state governments and the citizens. This fact emphasises the importance of services offered by Public Administrations and in the modern technological era, it is essential for Information Technology to provide solutions for transforming these traditionally offered services into electronic transactions that could be initiated over the Internet, aiming at the facilitation of the citizen's life, who is the eventual "client" of any government.. Although public administrations have strived over the last few years to meet this goal, their individual attempts resulted in isolated, ad-hoc systems, offering a small piece of the whole service bouquet. As the connectivity generated by the Internet is opening new opportunities in service delivery, public administrations are seeking ways to deliver integrated value-adding services though an Interoperable environment. The goal of a systematic service composition, which will guarantee eGovernment Interoperability, can be accomplished with an effective method of modeling the public services, in order to expose their interfaces and their actual workflow. Applying this method in Greek Municipalities by respecting the context of the emerging Greek eGovernment Interoperability Services Framework, various services have been analyzed, leading to corresponding generic process patterns.