If you were hoping to have a DiRT Showdown on the PlayStation 3 and Xbox 360 on May 29th then perhaps you should find something else to tide yourself over until June 15th because Codemasters revealed today that the game has been delayed on these consoles until that date.
The PC version of the game is still going to be available on Steam on May 24th so no worries there if you enjoy some PC gaming. The reason for the delay is to give the game a “clearer release window.” This usually translates into the fact that there are either A. too many games coming out at the same time or B. the game will be released the week before E3 and will be lost in the hype.