Google App Engine lets you run your web applications on Google’s infrastructure. App Engine applications are easy to build, easy to maintain, and easy to scale as your traffic and data storage needs grow. With App Engine, there are no servers to maintain: You just upload your application, and it’s ready to serve your users.

Testing and deploying of application on Google App Engine is via unfriendly command line interfaces which could be time consuming here is Google App Engine Launcher for Windows which provides GUI interface to deploy and run application on Google APP.

Similar Application is also available for Mac OS X developed by Google Employees in their 20% project time.

Google App Engine Launcher

Download Google App Engine Launcher

Checkout : 10 best Application hosted on Google App Engine.