Good app / process for organizing video snapshots into a storyboard? I have many hours of footage from a friend's wedding I want to set to a music video.  I'm using Adobe Premiere.  I already have the main story arch, and now I want to fine-tune the sequence of shots per scene/act.

I think what'd work best for me is to grab snapshots of the candidate clips and lay them out in an app that lets me sort and organize. After that, I want to run through the storyboard along with the song to see how well it fits.

Does someone know a good process or app for doing this?  Ideally, I want to replicate the process of using storyboard index cards and organizing them manually.  I imagine it's easier to do this all in software since the source material is all digital.  Free is preferred but I'll consider paying for something nice.

Left to my own devices I'll probably pull screen caps using Premiere or VLC and sort them manually in Windows Explorer.
I ended up using Trello.  It was nice in that I can lay out shots scene by scene, with each scene as a list.  Dragging and dropping individual frames (as png's or jpegs) for card cover images was super handy, as was being able to move around and organize the cards later on.

Being able to write longer descriptions and comment on each card allowed me to document why I wanted to use a shot, or decided against it.