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
As of Dec 30, 2017, this appears to be different (yet again). I did the following.
Logon to the Google Cloud Console, Select IAM & Admin then Settings (from hamburger menu on top-left nav-bar). This is a cascading menu. After choosing that I saw the following.
On the bottom left of the screen is a button/link labeled Manage resources, click on it.
After clicking on it, I saw the following screen, on which I selected the project name I wanted to delete and clicked the Delete ICON/button.
Then I was asked if I wanted to "SHUTDOWN" the project and to do so I had to enter the project ID number, so I did and then clicked on the SHUTDOWN button/link.
Hope this helps someone. The others answers did help me out but were not the exact steps I had to follow.
Important Note: The terms "Shutting Down" a project and "Deleteting a Project" seem to mean the same thing, so if you stumble across something that says "Shutdown the project" you have likely come across another way to "delete the project".
Deletion of projects is no longer available under the old Google Cloud Platform Console. To delete a project, open the latest console. Once done, you should be able to see a list of your projects as well as the delete icon(s) on the right side:
You must be a project owner to shut down a project.
Just found that Google doesn't allow you to delete project in old console anymore. For now, you need to click on project, then "Billing & Settings", you will find delete button there.
You must first disable billing before deleting any project. See link https://developers.google.com/console/help/#deletingaproject
To delete projects created using Google cloud console, you can use the following method:
1: Create a dummy gmail account.
2: Add the dummy gmail account as an owner of the project.
3: Login into the dummy gmail account.
4: Accept your role as owner of the project.
5: Visit Cloud console.
5: Go to Cloud Console -> Permissions and delete the main user from the project.
NOTE:
Other than Step 2, rest all the steps should be performed using dummy gmail account.
You may need to visit https://appengine.google.com/, select an application, then go to Administration -> Application Settings, scroll down half-way and click "Disable Application" under "Disable or Delete". One the next page you can also request permanent deletion.