Google SiteLinks
You may have noticed already that some search results in Google have additional links below them: 
These links are called SiteLinks as it is explained in the Google Webmaster Central blog.
Want such links to appear with your site results? Unfortunatelly you have little control over them. As Google explains:
“At the moment, Sitelinks are completely automated. We’re always working to improve our Sitelinks algorithms, and we may incorporate webmaster input in the future.”
From my own observations I can say that your site should be quite popular and have well organized menus for the links to appear.