more answers:
1) Personally, I wouldn't mess with Partition Magic to do your dual booting. I'd go with whatever boot manager your linux/unix (*nix) distrobution has. A current copy should set up the boot manager almost completely for you. LILO is excellent.
2) As I said *nix can use a variety of formats. Just partition the drive and let your *nix distro do the formatting.
3) Quite stable... I've never heard any complaints about any type of *nix formatting. (someone please correct me if this is not true, but I have yet to hear of problems with it)
4) Not sure what you mean by that one... I think you are referring to the approx. 8 gig architecture of the FAT32 formatting... it's not a big deal these days. Partition to the size where your heart is content.
5) Umm... no? once again, not sure what you're getting at..
6) False.. you are getting bad information, or outdated at best. There is no truth to that statement to my knowledge. That really doesn't make any logical sense if you think about it.
7) umm... not sure off hand. I don't know if there is a comprehensive comparison of ALL of them.
8) more than you think. There is Solaris (Sun), HP-UX (HP, duh), FreeBSD, Mandrake, Redhat, SuSe, AIX, etc, etc... those are the big ones... there are many others and I'm sure hacked versions that people have created on their own.
9) Decision... all dependant on your wants/needs. I'd suggest Mandrake/Suse to start out with... they're the most user friendly. But it all depends on you personally. I know people that swear by Redhat, and some that swear by Solaris... I swear by Mandrake.
10) PIII processors are fine... I'm a fan of AMD, but that's just stating a preference.
11) Not sure about AOL... I'm sure they probably have a *nix distrobution, but you may want to check into it. I know they have Instant Messenger or some variation of it for Linux, but I'm not sure about the full blown version.
Hope that helps.