Sample dates: October
Fare Availability: until March 2015. Must purchase at least 14 days prior to departure. Works both direction.
How to find fare: you can use USAirway, AA.com, or almost any other OTA websites (orbitz.com, priceline.com, etc)
As a celebration of the American Airlines and US Airways, flyers will be able to earn 50% bonus miles if flying on USAirways and crediting the miles earned to American Airlines beginning Jan. 23 thru March 2, 2014. Use promo code AAUSM to register before booking.
Fares cheap as $128 for roundtrip from Philly to Vegas! Wow. I see some availabilities in November. Act quick!