Davo has pretty much summed it up.
Try here
http://www.marcpeters.co.uk/videoeditingforum/
and look at the numerous guides down the left side of the page.
Like the rest of you, I am fairly new at this. I was lucky enough to buy a card that worked and with half decent quality at the first attempt. Also as you are probably finding, the more you learn the less you seem to understand!
Good luck fellas.