Monsieur Dreyfus has now opened bookings for June 2012.
I've already booked my usual - out Sunday 10th 23.00 Portsmouth-Le Havre; in Monday 18th 17.00 Le Havre-Portsmouth. Even with the addition of sleeper seats (at £24 each x3!!), it's still cheaper at £338 than the £404 last year. Brittany Pirates want nearly £500 for similar. I booked mine over the phone, as I'm going over with a caravan, but not bringing it back, and I could only do this on the website by booking two separate journeys which came to £385 - but only £338 over the phone.
So, as someone else has already stated elsewhere, it's cheaper to get in early.
Del