So it finally appeared (from the V4L mailing list) that modprobe ivtv was going to load the appropriate driver for this card into the kernel, so I ran it, and
I don't even know where to look for help
Hardrake isn't sure about the card; it has a Bus ID for the card, and knows that the Media Class is Multimedia_video, but has not picked up on the Vendor, Description or Module.
Now I'm wondering if I should reinstall Mandrake 10 from scratch. Hmm. I do have a copy of FreeBSD 5 that I've been meaning to try, so maybe I'll do that first.