United has announced a 20% discount on economy class awards to Europe from January 15 to March 13, 2013:

United and United Express operated flights
Booked between now and November 15
Roundtrip economy class awards for 48k miles.

I'll break this promo down and compare it to the discounted awards to Europe being offered by American and US Airways.

United

Roundtrip awards entirely on planes bearing United and United Express paint jobs between the continental US, Alaska, and Canada and Europe in economy class, flown between 1/15/13 and 3/13/13, and booked between now and 11/15/12 cost 48,000 United miles.