Services.google.com/urlconsole/controller is the URL to use if you want to remove your own site from Google's results or if you want to remove your own Usenet posts from Google Groups. You can only use this service after Google has verified your email address.
See also Google's removal help page.
Can I only remove my own site?Edit
No. Although the service is aimed at webmasters, you can also request removal of a page on another site as long as that page has the appropriate meta tags or robots.txt which show that the site owner does not want Google to index it. However, this service is only for sites with this meta data. The service is not for reporting spammers or for making copyright infringement notifications.
How long does it take?Edit
Pages are normally removed within five days. Google Groups Posts are normally removed within one day.
Removing directories, pages, and imagesEdit
This option lets you tell Google where your Wikipedia:robots.txt file is. They will check this, and adjust their index of your site accordingly.
For example, to prevent Google indexing your site at all, you could add
User-agent: Googlebot Disallow: /
Removing single pagesEdit
Remove a single page. This option is based on the page's meta tags.
If your page contains meta tags which tell Google not to index it, you can tell Google to remove that page from their index. For example:
<Meta name="Robots" Content="NOINDEX, NOFOLLOW">
This option is only for pages that no longer exist on the web. The page doesn't have to be your own in order to ask for the dead link to be removed from Google's index.
When you give the URL to be removed, you have the option of removing anything associated with the URL, Google's cached copy of the page, and/or the extract from the old page which appears in Google's search results.
Removing your Usenet postsEdit
You can remove messages that you posted from a particular email address as long as you still have access to that address. You will need to know the Message ID or URL of the post you want to remove.
See also Google's post removal help.