MS does not have live cd's.
I don't pretend to know all the mechanics of how a live cd works.
You plug it into your cd player, reboot your system and boot to that cd.
It utilizes your ram and runs from there almost as if it was installed.
You're limited on your capabilities of course, but it gives you a pretty good idea if your system is compatible or not as well as deciding if you like it well enough to install it.
As to installing to an external hd, yes, you can, provided as stated above your bios will allow booting to an external hd.
It's no different than dual booting on your internal hd.
Dual booting isn't all that difficult but does require some patience to grasp as there are almost as many ways to dual boot as there are to set up partitions and as many arguments on the best way to do it.
I myself have ran 7 different Linux systems on one hd.
If the distro you choose has virtualbox in the repo, [pclinuxos offers it, dunno about the 'buntu's] and you have about 20 gigs of hd to spare and ram enough to spare at least 512 megs, you can install windows [and most linux systems] to virtualbox and avoid the necessity of dual booting.
Viruses and spyware aren't a problem in Linux unless you plan on running a server.
Linux viruses try to target servers and the last virus I'm aware of is several years long gone.
Windows viruses and spyware cannot install to Linux and anyone wishing to try and write viruses or spyware for Linux is more or less urinating against a strong breeze.
The already put together Linux systems have their own repository and they don't let just anyone make packages and put them in that repository.
You'll get all of your packages from your respective repository so, again, unless you're running a server, an antivirus is like wearing a belt as well as suspenders.
As for a firewall, I'm on a router which is more than adequate.
Routers are extremely difficult to get past.
Most of the ready made distro's come with a firewall in any event.
As for the ipod, I don't have one but I've read on some of the forums where folks are writing to their ipods with linux.
Last edited by windtalker10; 05-01-2008 at 12:48 AM.