Direct link to delete your complete Google account, including ALL services (be aware!). See also http://www.google.com/support/accounts/bin/answer.py?answer=32046
If you're from the EU, and want to remove yourself from Google's search results, you can use the 'Right to be forgotten' form found here: https://support.google.com/legal/contact/lr_eudpa?product=websearch - success is by no means guaranteed while your request will be judged on various legal criteria. See the link for more information.
Publicly visible text/images often aren't properly deleted even when you succeed in deleting an account. Try editing or deleting them manually before deleting the account itself. If you're unsure what happens to your tracks you can always contact Google and ask personally. By the way, deletion requests don't necessarily mean your data will actually be deleted (e.g. due to legal obligations).
Si no puede encontrar ninguna información de contacto y todavía desea hacer algo (por ejemplo, una pregunta acerca de lo que se elimina, sobre la retención de datos, etc.,), usted puede contactar a los propietarios de dominio utilizando esta información.