U.S. Federal agencies are utilizing cloud computing and now have an app store, Apps.gov, which provides federal agencies and their staff with cloud computing applications. This includes business apps, productivity apps, social media apps, and cloud IT services.
Here is the video Apps.gov provides as an introduction to cloud computing.
Many corporations, and individuals, are still very hesitant to use the cloud, but hopefully the government's move to using the cloud will encourage others to use it. Especially if the government's use results in efficiencies, cost cutting, and being environment friendly.
How will cloud computing affect education? The Don't Waste Your Time blog just added a post on this very question. And he gives the "good" and the "bad."
You can also read how Google is playing a role in this.