Yes, US offers a seatmap - if all you're looking for is configuration - go to http://www.usairways.com/about/aircraft/ and click on the particular type of aircraft you'll be on. If you need one that shows what seats are occupied and what's not, you'd have to go through the process of buying a ticket on US' website (of course cancelling before purchase) or doing the same on ITN's website (www.itn.net) (I think).