Virtual Infrastructures (VIs) have recently emerged as result of the combined on-demand provisioning of Information Technology (IT) resources (consolidated by Cloud Computing) and dynamic virtual networks (introduced by Cloud Networking). By combining IT and network virtualization to realize dynamic service provisioning, the VI concept is turning the Internet into a world-wide reservoir of interconnected resources, where computational, storage, and communication services are available on-demand for different users and applications. A VI is fully virtualized, provisioned and managed by an Infrastructure Provider. During the VI¿s lifetime, the requesting user is given full control over the aggregation of IT and network resources. The innovation introduced by VIs brought along a set of challenges requiring the development of new models, technologies, and procedures to assist the migration of existing applications and services from traditional infrastructures to VIs. These challenges are discussed in this work as well as a set of innovations to manage VIs.