When I Google certain things (lets say 'Zeldman') I get zeldman.com as number one result. But below that description farmed from his meta tag there are key sections of his site, with their respective urls beside the section name. I've been seeing that more often. How are these sites doing this?
That's a good question, for example if you search for "css beauty" you get the same result. I have a feeling it has to do with how long the site's been up and traffic, but there's no way to know that.
It is the Sitemaps. Google has very specific ways you can submit your sitemap in the Webmaster Tools they provide. There pretty easy XML files to create and once you submit them and they get crawled Google will start to display them.
they're not related to Google Sitemaps... they're called Google Sitelinks. They're completely automated and based on an algorithm that no one outside of Google has been able to figure out exactly (at least to my knowledge). It is known that you have to be the first result for the sitelinks to appear.
The more "authority" your site has, the more likely it will show other results from your site. CSS Beauty has a pagerank of 7, and despite all of the pagerank means nothing crap, having a pagerank of 7 is a very good thing to have. Also, having your title tags formatted the same way throughout the site also helps. Wordpress and other CMSs do this for you. The more authority you have in google the more it will show for the results. Try searching for microsoft. Anyhow, that is as much as I can get into it without the firm I work for getting upset.
This is the answer. Google decides where people are going on your site, and determines the hierarchy and important sections, and shows them as shortcuts.