You can go to USAir.com and see the itinerary. If you want to see it at UA's site, you'll need to replace your US number with your UA MP number.
From the Q&A:
How can I view my reservations?
Click on My Itineraries from the Book travel box on the homepage to access your reservation. You will need to log in with your Mileage Plus number and united.com password. Your reservation must have your Mileage Plus number on it and be on a United, Ted, United Express or code share flight operated by United. The reservation can be booked through any channel – united.com, United Reservations, or even other web sites – and as long as your Mileage Plus number is included in the reservation, you can view it on united.com.