i've gotten my zip drive to work in OSX PB.
i haven't tried this with OSX 10.0 yet though.
system: blue g3 350, adaptec scsi card (forget number 3096 or something, 20MB/s), scsi zip drive.
to get it to work in PB i booted up with a mac formatted disk in the drive, power on. it worked like a piece of cake. i haven't gotten it to work in 10.0 yet, although i think the disk i tried isn't mac formatted.
on any mac pre X you can connect a scsi zip and boot up, automatically mounting the disk with no driver or guest software. well at least i can.
don't know if the same is true for usb zips...