Well, release years anyway, according to Jeffrey Katzenberg.
"The fourth film will come out in 2010 and the fifth in 2013," is what Katzenberg told an Australian newspaper while he was down under introducing "Shrek the Third" to another continent.
This should come as no surprise to anyone: All three of the "Shrek" flicks have been monster hits at the box office. (Good to know we still have three more years till the next one, though.) Perhaps someone can spend part of the next three years writing a better screenplay than the last one.
Source: Courier Mail