Why do some Google results show multiple urls?

[apostle]

Some sites.. Like Amazon.com and www.marketingtips.com return the main url and 4 or 5 seperate urls beneath that. How do they do that? Do you have to pay Google? Thanks

[grwalker]

On a similar vein....this is happening with one of my sites where we rank 4th and 5th for the same keyword.

Does this mean:

We are recignised by google as an authority site?
Or
We just have two pages targeting the same keyword?

It's presumably a good thing that two pages come up right?

[incrediblehelp]

Discussed here before:

Post subject: Sitelinks and Google

They are called SiteLinks.