Star Wars: Episode III:The Force.net have rounded up some bits on the apparent looming promo schedule pushing the next Star Wars film...

The timeline: the marketing campaign starts officially in September, with the Classic Trilogy Saga DVDs and the Ep. III documentary included (which is very important because they no doubt plan to draw new fans to the saga with this). Then November with the release of the teaser poster, the trailer in March and the Movie in May 2005.
Brian B. at Movieweb
Brian B.