Run your web apps on Google’s infrastructure.
Easy to build, easy to maintain, easy to scale.

1) Register a free account here https://appengine.google.com/.
2) Create an Application here https://appengine.google.com/start/createapp.
3) Download Google App Engine SDK for Java from here http://code.google.com/appengine/downloads.html#Google_App_Engine_SDK_for_Java.
4) Unzip appengine-java-sdk-1.4.2.zip in your favorite drive like “D:\appengine-java-sdk”
5) Now download apps svnmedia.zip “D:\appengine-java-sdk\demos” and unzip here “D:\appengine-java-sdk\demos”
6) Edit application XML file “D:\appengine-java-sdk\demos\svnmedia\war\WEB-INF\appengine-web.xml” to the name of the application like “svnmedia”.
7) Run below commands to upload your application, make sure JDK in system classpath variables

D:\appengine-java-sdk\bin> cd D:\appengine-java-sdk\bin
D:\appengine-java-sdk\bin> appcfg.cmd update D:\appengine-java-sdk\demos\svnmedia\war

Finally you can check your application here http://svnmedia.appspot.com/

Please check features for Google App Engine: http://code.google.com/p/googleappengine/issues/list

As of May 10, any organization that signs up for a new account will be required to use the paid Google Apps for Business product in order to create more than 10 users. Google honor our commitment to all existing customers and will allow you to add more than 10 users to your account for svnlabs.com at no additional charge…

Reference:

http://www.builderau.com.au/blogs/

http://www.liventerprise.com/tool/Google_Apps/

http://images.google.com/