It's that easy. And it's FREE.
Do you want a window seat with a view? An aisle seat for convenience? With a free account, you can set up one alert at a time using the Any/Window/Aisle Seat options.
Book your flight with any online service, offline travel agent or with the airline. When your alert arrives, you can contact them to change your seat assignment to switch to the preferred seat.
It's only available on ExpertFlyer.