United and its merger partner Continental are offering a new mileage bonus for anyone who travels in business or first class from the U.S. to London between now and December 31st.  The way it works is that the first round trip you take will earn you an extra 25,000 miles; the second another 35,000; and the third and fourth another 45,000.  That’s 150,000 miles you can earn if you happen to fly to London a lot and are lucky enough to go in business or first class.

The bonus miles will be awarded automatically but you will need to register with United first.  You can do that by visiting their web site at www.united.com/offer/MPI051.  Registration is free.