Google sitelinks are the navigational links displayed in search results, below a site (this typically happens for your site if you search for the site’s title, but note it only happens for some sites out there). Google determines these sitelinks automatically so you usually don’t have a say in that, but now you can disable specific sitelinks. Just go to the Google Webmaster Tools, verify your site in question, and switch to the Links -> Sitelinks menu entry.
I can see the menu entry but don’t see the option to disable sitelinks yet for one of my sites which has sitelinks, but as I only verified that site just now, maybe it simply takes a bit of time. The official Google Webmaster Blog though posted a screenshot of what it should look like.Google, Google Webmaster Tools, GWT, Site Link, Sitelink
Source:→ google blogoscoped