This week's giveaway is in the EJB and other Java EE Technologies forum. We're giving away four copies of EJB 3 in Action and have Debu Panda, Reza Rahman, Ryan Cuprak, and Michael Remijan on-line! See this thread for details.
According to what I have understood: Its on demand service- Be it hardware or software resources. So we have Software as a Service(SaaS), Platform as a Service(PaaS). So the cloud takes care you your computing needs- You just have to specify your requirements. Good examples of this are- Amazon Cloud, Salesforce (SaaS), even Google with its Google Apps.