Go here http://www.ubuntu.com/desktop/get-ubuntu/download
Then choose 10.04 in the drop down and whether you want 32 or 64 bit

After I sent my question, I found it at
http://www.ubuntu.com/server/get-ubuntu/download and downloaded both 10.04
and 10.10 before realizing I had the wrong ones. So I went to the address
you gave, and I see that there's a desktop version and a netbook version. I
have a laptop, and when I make the font big enough to see, I have to scroll
around a lot to see the whole page. Being that the netbook version is said
to be designed for smaller screens, would that be more appropriate for a
laptop, though it's a full-sized laptop?

I notice that Windows 7 has its own image burning utility, so I guess I
won't need that.

So after I burn the ISO image to disk, and verify it, if I partition and
install from the CD I burn, will my Wubi-installed /home on its virtual
partition be safe and sound for me to recover, or will the new installation
wax those files?

You can try the netbook version first to see if it's better for you
regarding the screen and if not suitable then go for the full version
and adjust the screen resolution to something less than the 'native'
one. You'll get a slightly less sharp image but it will have larger
fonts etc...

As far as I can tell there's only one netbook version and that will
automatically detect 32bit / 64bit on installation - too much to fit
onto a CD for a standard install so that's why there are two versions
of those :-)

The balance between screen resolution / font size / amount of
scrolling needed is a personal thing and what works for one doesn't
work for another. It's question of playing around with settings until
you find what suits you.

It's best to back up from a live cd before you start altering and
installing (that's just my oppinion). To burn iso file, in window I
use a program called infraburner. It's freeware and dead simple to
use. I can find a link tomorrow, but a web search can probably turn it
up. I think it was the ubuntu website that suggested that program.

10.04 is LTS, Long Term Support,
it will be supported for 3 years till 2013
whereas 10.10 only lasts until April -
as I dont want to learn new windowing every 6 months
I'm sticking with 10.04LTS until convinced to upgrade.

I have a 64-bit machine, and I notice the netbook version doesn't
have a 64-bit option. That important?

My netbook has an atom processor. 32bit not 62bit. 32bit will work on
both 32 and 64. The remix will install and run on a laptop or desktop
but I think that is going the wrong direction, for giggles I did install
remix on my laptop and it works fine.