Google detailed results

i didnt know where else to post this, but am sure someone can guide me in the right direction on this one:

certain companies get their sites listed in google with extra line items (not in the paid ad section or anything)…for example, if you search for “Kirupa”, you get the regular part of the search result which is the page title, description, link…but you also have a small list of links of the pages within Kirupa below that (Flash, Forums, Photoshop, PHP)

How are those extra items getting there?

Cause if you search for something like “Canlaw” (a Canadian Law site), you don’t get those details, just the plain simple link and description which is the usual Google returned result set.

Any advice, direction?
thanks.