Someone is using the service Google Flights to look for air tickets? The service was launched in September 2011 and is only available in the United States. You can search for flights from American cities to the rest of the world. Last day there were rumors about Flight Explorer, a similar service, but with more options and filters.
I took a look, I did some simulations on different destinations, I applied some filters and it seems useful. We have searched for the cheapest flight to Bucharest, with complaints from New York, and you can see the result below.
You have filters to choose the alliance with which you want to fly, the duration, you can set the time when you want to leave the country, the time ranges, etc. The interesting part is that Flight Explorer looks like a complement to Google Flights and not a replacement. I haven't seen any official information about Flight Explorer, which makes me think it's still in testing.
Below you have a number of interesting print screens. Reservations can only be made through Priceline.com and Orbitz.com!
You may find prices even lower than those indicated by Google. It depends on the search and booking services. Flight Explorer is available just like Google Flights.