Advice about amateur documentary filmmaking? If you are in the Toronto area, check out the Liaison of Independent Filmmakers of Toronto and look at some of their courses. LIFT has a lot of courses for documentary creators. There are courses for DVD, video and audio editing, but there are also one on narration techniques, sound recordign in the field, and on-site lighting.
Cameras. What sort of price range are you looking at?
You should get a digital video camera. These use Mini-DV or Digital-8 tapes, and are in most price ranges now, and offer direct video transfer to personal computers by a single cable, which is also used to control the camera. This is much easier than capturing analogue video from an older camera or from a VCR.
Do you want to edit high-definition or standard definition video? Some high-definition cameras are withing the “determined hobbyist” price range now.
Make sure your camera can record in low-light conditions. I didn’t when I bought mine, and I now have a camera that will barely work in a regularly-lit room at night. 
Even so, you will also probably need external lighting. I don’t know much about this yet.
You will need a computer to edit the video on. Ideally it should have a DVD recorder so that you can burn your final video to DVDs. It will need to be powerful (in Windows-PC terms, at least a 2-GHz processor); it will need a lot of memory (at least 512 MB); and, especially, it will need a LOT of disk storage space for the video files (at least 80 GB).
What kind of computer do you have, or do you plan to get one?
You will also need video/audio editing software. If you are making DVDs, you’l need DVD-authoring software for the DVD menus. Basic versions of these are often provided free with DVD burners, but to take full advantage of the possibilites of the medium, you’ll need somo standalone software. I use Adobe Premiere, DVD-Lab Pro and Photoshop on the PC, plus various other utilities. There are equivalents in the Mac and Linux worlds.
If you’re doing family history, be aware that you can also put slideshows on DVDs. This is perfect for all those family pictures, and you can have voiceovers as well.