Okay, here it goes - I'm giving up on the Photoshop tutorial. I haven't worked with it in ages (I'm a Fireworks girl, myself) and my computer is too slow.
In order to extract a background, there are different ways to do it - and they are all mentioned right here. So, use that awesome tutorial to play around with it?
I know that I usually used the Extract filter if the images were clear (i.e. with a lightbox), and added a vector mask when they weren't.
Gimp is still coming, as is Fireworks - my own playground.
Susan - looks like they moved the site. I have updated the link according to their new site. Hope this helps!