Looks like this :
when 1st installing windows 2nd linux = all ok ;) lilo/grub automatic find another OS
but when you will install linux and then windows you can spot some problems, cause micro$oft's shit overwrites your MBR and your lilo/grub are annihilated ;) then you need to run Ur *nix from floppy or bootCD and install proper boot loader ;} it's nice explained on dozens of webs so i'll skip it ;P there is a few other possibilites to overcome this problem but one i wrote is good and enough :}
2. hardware ;P
modems are most shitty devices to set 'em up under linux ;P but i would bet that on some BSD it would run smoothly ;) i dont remember but afik netBSD is most compatible distro ;P
i hope i helped a bit ;) greetz ;P
p.s :)
http://www.xs4all.nl/~golverd/tuxpage.html
and
http://www.yolinux.com/TUTORIALS/LinuxTutorialRecoveryAndBootDisk.html
good article and i like language used in it ;)
p.p.s
you can seek you way by mr G :P