Price increases could happen at any time. Information has already leaked out about UPH's increasing in price for 2005 which would indicate a January increase in them. UPH's last were increased in February 2004.
Most of the other tickets went up in March 2004 but Disney has been doing cute little things with their price increases lately, the most recent of which was raising the single day admissions to the water parks and DQ by $1 in October. So rather than doing across-the-board increases, they have started raising some here, some there, and a few others later still.