I do not run Fedora, but the install options for all distros seem similar. If Fedora follows suit, then:
i386 - Install DVD
will be a generic intel architecture setup ... in general, this is the most compatible version
x86_64 - Install DVD
will be a 64bit (vs 32bit) version for intel architecture ... somewhat less hardware friendly as some users have difficulty finding good 64bit device drivers
ppc - Install DVD
will be a PPC processor (that is, the PPC processor unit used most notably in pre-intel apples) specific version ... NOT what you want.