According to JoBlo.com, A teaser trailer for “Lady in the Water” will be shown in front of “Harry Potter and the Goblet of Fire”. The trailer isn’t “attached” to the movie like the teaser for “Superman Returns”will be, so it’s not a definite that all theaters will play the trailer. But having a trailer “accompanying” a movie is better than just being “in the can” so, in most cases, it will be seen with HP4. A teaser poster is due out around the same time frame.
Thanks to Dr. Malcom Crowe in the Forums