A key factor in preserving the rights of free movement of labour and goods in an eGovernment age will be the availability of cross-border identity services to give citizens and businesses equal access to eGovernment services across the EU. The main purpose of this paper is to present the research outcomes of a FP6 European project focused on the development of an Open Identity Management Architecture for cross-border identity services. The emphasis is put on the evaluation of the two trials, performed for demonstration and validation of the designed and developed IT solution. The first trial is devoted to the challenging aspects of the electronic cross-border citizen identity management and addresses the European Form E101 exchanged between the EU countries when an employer sends an employee abroad to work temporarily. The second trial covers cross-border business identity management and deals with e-procurement. The objectives of the research undertaken in the E101 and eProcurement trials, apart from the underlying proof of concept, were to provide knowledge about performing translation services between different Identity Management standards, and specific knowledge in the realms of identification, attribute provisioning, service discovery and authentication. The research scope included validation of the existing Open Identity Management Architecture specifications and testing the implementation of several Identity Management processes (identification, Authentication, and Attribute Provisioning), theoretically examined and specified in the architecture development. Furthermore, through enabling the communications between disparate systems (Gateways, PEGS/identity Providers, eTender applications) the technological insights were gained. The trials were subjected to both, technical and user acceptance evaluation, performed by an international group of academics, independent from the development, integration and deployment team. The paper focuses on the user acceptance evaluation. A qualitative approach is used, because it is considered more appropriate when trying to elicit user opinions regarding the results. The trial user acceptance assessment plan and evaluation methodology includes the following stages: preparing for the evaluation, managing the evaluation process, analyzing and reporting results. The focus group discussions are organized as interviews, involving all stakeholders participating in the trails implementation. The outcomes of the trial evaluation revealed that they were implemented according to the plans, and complied with the user requirements. They were useful in showing the potential of electronically-enabled cross-border Identity Management and therefore could be used as a mobilization vehicle for the required revision of the legal framework regarding the implementation of Pan-European eGovernment services.