Google just updated it's toolbar, and I was poking around and noticed something very interesting.
Under the Buttons tab, there is an option for "Search USA".
I've been messing around with this, and it really does work. Here is a REALLY interesting thing - I'm hosted in Canada and use a .com as my main domain.
When I search for "mcanerin" using Search USA, my .com site disappears, but my mcanerin.us site shows up as #1.
So Google finally counts the .us TLD. Very interesting, and may have grave effects for many .com companies if this functionality moves into the mainstream.
Search USA for "mcanerin":
I guess it's time to register a bunch of .us domains ;)