Description of problem: initrd (initial ram disk) which Fedora installs during installation process contains only modules for the current storage controller(s). Thus if you insert your HDD into another computer then your Fedora may not boot (most likely will not boot). I suggest creating a 'generic' initrd which contains modules for most SCSI/PATA/ATA/USB HDD controllers, so that it is possible to boot your Fedora in a different environment. Of course, upon kernel updates this initrd should be updated automatically.
Changing version to '9' as part of upcoming Fedora 9 GA. More information and reason for this action is here: http://fedoraproject.org/wiki/BugZappers/HouseKeeping
We've switched as of Fedora 10 to building in a lot of the "general" modules. And after Fedora 11, we will likely be switching to dracut instead of mkinitrd which will do something like this. So for mkinitrd itself, going to WONTFIX