In Windows XP (since I was just getting started with
Kubuntu), I used a program called InfraRecorder, you can download it
for free. In that program, just open it, click on "Action" and then
"burn CD image". A box will open up where you can select which image
you want to burn. I'm still so new with Kubuntu that I haven't found
how to do this there yet.

>Now I have such files for v7.04 and v6.06.1. Assuming that I can get
>the right material on a disk, which of these is considered better?

I'd use 7.04. I initially tried 6.somethinorother and my
wireless connection (802.11) didn't work. When I went to 7.04, it
worked fine. I figure there must be other stuff that got upgraded
like that, too.