American Express Platinum Card holders lost access to the US Airways (and American) Clubs after March. Bloggers pointed out that the Priority Pass Select Card that comes with the Am Ex Platinum can still get you into the clubs (just with no guests).
Unfortunately, that won’t be the case.
From the DCA US Airways Club:
(Edit: WordPress let me fix the photo!)
Starting March 22, 2014, Priority Pass will not get you into a US Airways Club.
And note the American lounges are not on the website either. (I wouldn’t expect them to be).
If you would like a credit card that gets you access to the lounges, check out the (pricey) American Airlines branded Citi Executive Platinum Card.