Just what I was looking for...

I spent the better part of two hours scouring the internet for find an OS X program to do exactly this, when in all actuality all I needed was 2 minutes on the App Store.

The only things that could make this program better would be:

1. True timecode support for the the timestamp (frames, not milliseconds)
2. Preview of what the sheet will look like with generic frames as placeholders
3. Interval based sheets, eg. one frame every 20 seconds. You could set the number of frames wide the sheet will be, and it will just add rows as needed.

Great app!

the_beerd about Movie Thumbnails, v1.1.0