Google App Engine Plugin for eclipse can be installed using the Help menu –> Install New Software menu option.
Click Help Menu and select Install New Software from the list of available menu option.
In the Work with text box enter the URL http://dl.google.com/eclipse/plugin/3.6 and click the Add button.
Enter the Name in the Add Repository and click OK button. Select Google Plugin for Eclipse 3.6 and the required SDK’s as shown below.
Review the items to be installed in the next screen and click the next button.
Then Review the licenses and click the Finish button. This would start installing the selected Software.
If you get the following Security Warning message, click OK if you want to continue installingthe unsigned content.
Click Restart Now button to Restart Eclipse for the installation changes to take effect immidiately.