EuroVO-AIDA aims at unifying the digital data collections of European astronomy, integrating their access mechanisms with evolving e-technologies, and enhancing the science extracted from these datasets. The concept of a Virtual Observatory (VObs) is that all the world's astronomical data should feel like it sits on the astronomer's desk top, analysable with a user selected workbench of tools and made available through standard interfaces across the whole range of astronomical research topics. VObs is embraced as a world-wide community-based initiative with the potential to transform and restructure the way astronomy research is done. Euro-VO is the European implementation of this idea, and the EuroVO-AIDA project is proposed to lead the transition of Euro-VO into an operational phase. EuroVO-AIDA integrates the technology, networking and service activities of Euro-VO into a fully functioning eInfrastructure. It will establish a Registry of VObs-compliant resources; support the network of data centres in deploying the VObs eInfrastructure; co-ordinate development of user tools for science extraction; and disseminate results to the astronomical community and identify their needs. The VObs interoperability standards will be updated taking into account feedback from implementation by data centre and from science usage. Specific emphasis will be placed on data access and data models, and on assessing innovative use of emerging technologies such as Web 2.0 by data centres for continuous improvement of the eInfrastructure. The result will be an operating knowledge infrastructure that enables and stimulates new scientific usage of astronomy digital repositories. Coordination of EuroVO-AIDA activities with the international VObs community is ensured, and discussions with other scientific communities will help to identify relevant generic tools and environments. Service activities are also identified for the support of outreach to higher education and the general public.