Blu-ray 4/3/12
20th Century-Fox is releasing Titanic on Blu-ray on April 3, 2012.
UPDATE: Fox has delayed the release of the Blu-ray until sometime later in 2012, probably around September, apparently to coincide with the release of the Blu-ray of the 1997 film. I think they made a mistake delaying this disc.
Like Criterion's new edition of A Night to Remember due in March, this release is obviously timed in anticipation of the 100th anniversary of the sinking on April 15.
Retail is $24.99. The disc has the same bonus features as the DVD.