Why do some sites have one listing in the SERPS and then another below it but indented? How do you achieve this double listing? Is it easy to achieve?
I think this happens whenever Google finds to relevant pages on your wesite, typically a detail page and a snippet on the homepage. In this case both will get listed and one is indented to show that it is just another representation of the same website/hit.
So to engineer this, I need some info on the homepage and then dedicate an internal page to it too but with much more detail? What about links, anchor text and so on?
The indented results are called "Supplemental Results". I would not worry too much about how to make them appear - any well designed site should automatically have the homepage targetted to the general theme of the site and then other pages targetted to specific sections.
I want to know how to make them appear so I can take up more real estate in the SERPS. For example, if you have the home page targetted to the specific phrase, how can you also have a supplemental result show up?
If my site is about cheese I could mention loads of cheeses on the homepage and have some information about cheese. I then create a page about cheddar cheese and write some stuff about cheddar cheese on it. When somebody searches for cheddar cheese both pages get shown with on being supplemental (indented).
No, they're not. Supplemental Results are results that come from Google's supplemental index of less-important and less-frequently-crawled pages, and they are explicitly labeled as such. See http://www.google.com/support/bin/answer.py?answer=12286&topic=365
An indented result occurs when more than one page from the same site rank such that they appear on the same page of search results. Rather than listing them separately, Google displays the highest-ranking page in its normal position, and then indents the second result instead of displaying it further down the page. Subsequent pages from the same site are not displayed.