Cloud computing promises to offer great opportunities for research groups; however when researchers want to execute applications in cloud infrastructures many complex processes must be accomplished. In this presentation we present the e-Clouds project which will allow researchers to easily execute many applications on public Infrastructure as a Service (IaaS) solutions. Designed for being a Software as a Service (SaaS) marketplace for scientific applications, e-Clouds allows researchers to submit jobs which are transparently executed on public IaaS platforms, such as Amazon Web Services (AWS). e-Clouds manages the on-demand provisioning and configuration of computing instances, storage, applications, schedulers, jobs, and data. The architectural design and how a first application has been supported on e-Clouds are presented. e-Clouds will allow researchers to easily share and execute applications in the cloud at low TCO (Total Cost of Ownership) and without the complexities associated with details of IT configurations and management. e-Clouds provides new opportunities for research groups with low or none budget for dedicated cluster or grid solutions, providing on-demand access to ready-to-use applications and accelerating the result generation of e-Science projects.