Checking your US Airways flight status is always a good idea when flying the carrier. If a delay occurs you might be able to just leave home later.
Alternatively, if a cancellation has happened or is imminent, you can be one of the first people to call the airline for a rescheduling. This will give you a much better chance of getting a seat on a flight that resembles you original itinerary.
I find the Google homepage the quickest way to screen for a flight status. All you need to do is enter the flight number (no spaces) into google.com (other local versions of Google often do not work).
Google will compare your query with the flight database and bring up the flight status above all other results.
FlightAware.com does not use the two-letter IATA codes, so you will need to enter US Airways into the search box to get to the result.
Once you jumped over that hurdle, you will get a very detailed page with historic departure/arrival times for the flight in question. This helps determining the likeliness of your flight being on-time today or tomorrow. It also shows the likely flight path for the aviation geek in the family!
Now that US Airways is merging with American Airlines, I also started using the AA app on my iPhone to double-check a US Airways flight status.
The best results in tracking changing arrival times for US Airways flights I had were with the free FlightAware app for my iPhone. The data was much more accurate than what would come out of the American Airlines computers. It even provides a little tracking monitor to show the flight path.
If I'd only be able to have one app for US Airways flight status – this would be it.