From Creative Workflow Hacks:
iPhotoToAESlideshow allows you to export an iPhoto album to a slideshow in Adobe After Effects
iPhotoToAESlideshow uses a JSON formatted export file from an iPhoto album to generate a slideshow via Adobe After Effects extendscript. Transitions available in the slideshow include:
"Cross Dissolve" Transition
Sequences the album and overlays a fade from 100 to 0 and 0 to 100 over the transition duration.
"Just Import Photos" Transition
Imports the photo with current metadata, which currently is only the caption.
(This is available only in After Effects 7 and above)
"Gradient Wipe" Transition
Sequences the album and creates an "Edit Gradient" comp which is the gradient selected in the filter.
Picks a random transition from the choices above.