My question is pretty simple: who specifies the formatting of these kinds of listings? I had a client ask and I honestly don't know whether this is something Google does itself, or whether it's some kind of formatting option declared in a Sitemap XML file. Thanks for your time...
Google does it itself when you become a trusted and valued site i.e. ITV has almost 200 thousand backlinks, but with 20-40thousand good backlinks you can get these listings. Google will generally pick the most popular 4 sublinks off your site and place them under the main listing
They are called sitelinks, and here's what Google has to say about them. http://www.google.com/support/webmasters/bin/answer.py?answer=47334&topic=8523 You can't do anything to make it happen (with a sitemap or anything else); it's determined algorithmically. It happens when several pages on a site rank equally for the search term in question. cheers ~ Denise