When I have a photo like that, I have a quick simple fix: in GraphicConverter (like Photoshop & GIMP), I use the Levels too to move the centerpoint somewhere between 1/4 to 1/2 way towards dark, then I drastically reduce color saturation (-20 to -50). I get a photo that looks black & white or halfway to black & white, but you can clearly see everything.
I've been told that the cheapest piece of software that will let me do that with a video is Final Cut Express, for $300. I don't have that many videos, and I don't need most of Final Cut's features; $300 is serious overkill. But it would be nice to make a few of my low-light videos watchable. If you have video editing software that can do this, and would be willing to process a few .avi files from my camera that I can send you, let me know.
I've been looking for a way to fix these videos for months. I'm asking now because because I got a video of the pediatrician's speech at the MoveOn kids' health care rally in Cambridge this week, and the sound quality is pretty good, but it's too dark. I'd really like to post it, and contribute it to MoveOn, before the SCHIP veto override vote happens (possibly this month).
( here's the video )