The Jordan's IMAX Theater is reporting that AOTC will be cut by 23 minutes to conform to most IMAX systems:

The IMAX edition, which will be distributed by Twentieth Century Fox "exclusively to IMAX theaters," will be trimmed from its original 143 minutes to fit the 120-minute capability of most IMAX platter systems. A LucasFilm spokesperson told LFX that the editing will "maintain the integrity" of the story.

Thanks to Ross for the alert.

Update:
We'd like to know what scenes you'd like to see cut from the movie to make it flow better. As we've had so many emails, please submit your responses on the Fan Speak page by clicking here, where we will list your scenes.

Update 2:
All responses have now been added and you can check them out here. Thanks to everyone who took part.