Google has added a new navigation panel to the left-hand side of most results pages. Many of the options have been available for while (I blogged about it in The Ides of October 2009 "Filter & Refine Results Using Google's Search Options Side Panel"), but was originally very subtle, and many people didn't notice or use them. Now Google has re-designed the navigation panel with icons & bright colors to bring attention to the ability to refine search results by types of content.
What will show up on this new left panel depends what you're looking for; Google will suggest the tools that are most relevant to your search. You can always click the "More" icon to see additional tools & categories.
The “everything” search option is the default search type.
Watch this short (a minute-and-a-half) video for a quick overview of how to "slice & dice" your search results: