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
Tty to change back to old console design.. You can find delete button there.
This is the old url https://code.google.com/apis/console/
Then you click in the left sidebar on the project name, you'll have a "delete" link :)