MAXjet is offering reduced fares on summer travel between New York and London for $599 each-way as well as Washington DC and London or $499 each-way. These fares are, of course, based on a round-trip purchase, and are good for travel from April 16 through September 15 for New York, and from May 24 through October 28 for Washington, DC.
From New York to London, traveling from June 13 through June 20, we found a fare of $1,346 round-trip, including taxes. We followed up with the same dates on Orbitz and actually found a better fare of $1,192 round-trip, with taxes, on MAXjet. Either way, it's much better than the next lowest business class fare, which is $2,310 on Icelandair.
We had no problem finding that $499 each-way (or $1,146 round-trip, with taxes) advertised sale fare from DC to London on the MAXjet site for travel on July 19 through July 26. Keep in mind, the best coach fare listed on Orbitz for this trip is $950, so that jump to business class really isn't that astronomical, especially for peak summer.