In regards to the floppy-issue:
WHAT are they saving to floppy?
Keep in mind , that most formats get over from one OS to the other just fine.
If they are just saving documents , text-files , images , etc. there's no problem.
It only gets nasty if they try to safe actual programs and/or scripts.
For example : A PDF on Linux is exactly the same PDF (bite for bite) on Windows or Mac.
Just take care of the formatting of the floppy.
(Or rather : go with the default preformatted stuff : works.)
As for the internet : There are several good sites about getting a winmodem(some of them at least) working under linux.
Linmodems cpmes to mind , for instance.
You might take a look at the HOWTOs on this very same site.
And , if I may state so boldly , if they are REAL computer.newbs , I'd advice them to quit that beginners-course and start learning Linux instead.
(Would be helpfull , if you offered to play the tutor in that case.)
It's easier to teach a non-tainted mind.....