The reason Prince of Persia was delayed 1 year:

[GreenScar]

IGN.com has posted the 2 reasons Persia was delayed 12 months:

Now Jim Hill Media claims there are two other reasons why the Mike Newell-directed game-to-film got bumped to 2010. A source for the site claims that the studio and producer Jerry Bruckheimer, who previously teamed for the franchise, were conscious of the cost of rushing to get special effects done in order to meet a locked-in release date, something they learned on Dead Man's Chest and At World's End.

"We're talking about tens of millions of dollars being spent on overtime, bonuses and incentive payments," JHM's source claims. "[These costs] really cut into the profit margins on those Pirates sequels. Which is why -- just as production was getting underway on Prince of Persia -- Disney & Bruckheimer decided that they couldn't afford to make the same mistake again. This time around, they were going to allow themselves sufficient time to get all of this film's visual effects done at a reasonable price."

JHM also suggests that Disney "wanted more time in order to co-ordinate a company-wide promotional plan. So that every possible platform at Disney (i.e. Disney Consumer Products, Disney Parks & Resorts, ABC, the Disney Channel, ESPN, Disney.com et al) could then be used to leverage this brand."