It seems that, from Google Cloud Console there is no way to delete a project.
Note: As of 2013-09-19 this is no longer an issue because Google had fixed
https://cloud.google.com/appengine/docs/python/console/?csw=1#delete%5Fapp
Since the console design has changed, many of the given solutions here won't apply anymore. Here is what Google help says here: https://support.google.com/cloud/answer/6251787?hl=en&ref_topic=6158848
To shut down a project:
- Go to the Cloud Platform Console.
- Open the console menu Gallery Menu on the top left and select IAM & Admin, then select All projects.
- Find the name or project ID of the project you want to shut down, then click DELETE PROJECT. A confirmation screen describing what will happen appears.
- To confirm, enter your project ID and click Shut down.
Shutting down a project stops all billing and traffic serving, shuts down any Google Cloud Platform App Engine applications, and terminates all Compute Engine instances. All project data associated with Google Cloud and Google APIs services becomes inaccessible.
After a 7-day waiting period, the project and associated data are permanently deleted from the console.
As of July 2017 the waiting period has increased:
After a 30-day waiting period, the project and associated data are permanently deleted from the console.