Even if the PC cruise sells out on Monday, if you really want to go - don't give up. A LOT of people will drop their reservations in the months to come.
We ended up booking our Aug. 2008 PC cruise 8 months prior. That cruise had originally sold out on the day it opened up for reservations. When we finally determined that we could actually go on that date and called DCL, the
CM told me that they had many cancellations since the original booking date. I think the Jan. date will even be harder for people to actually commit to, especially those with school children. It seems lots of people have a "book now, decide if we can really go later" mindset.