Apple - Is there an app that will convert a movie to an image sequence?

You can also use ffmpeg:

ffmpeg -i input.mkv -r 0.05 image_sequence%06d.png

-r 0.05 = 0.05 Hz = 3 images per minute. It sometimes includes a few extra frames from the start though. Without -r it saves every frame.

Yup, you still can do it with Quicktime Player. Download it from here. I believe you can also install it from the Snow Leopard install disc. I'm not sure about the Lion install download. Open the movie and click File>Export:

Then you can select Movie to Image Sequence:

Set your destination folder and watch Quicktime Player do its magic.