Predominantly used in scientific contexts, Grid Computing imposes constraints related to the underlying infrastructure, forcing in many cases users to rethink or rewrite their applications. Inspired by Amazonpsilas EC2 model, this paper presents a virtualization based system (GliteVM) that allows users to address this issue allowing them to execute any existing application in a gLite based Grid infrastructure without changing their current work setting and with a limited effort. The proposed solution can also have a wide and deep impact on the enterprise world, playing an important role in a variety of areas (from innovations to e-commerce, from social networks to research) where requirements of scalability, high-availability and security are expected.