In response to a friends question today, I have dug up some information on the Iomega Zip drives. Specifically, the concern was using the drive in a DOS Only system, and almost everything these days is made for Windows only. Forget about it if you have Unix, Mac or DOS only.
So without further hesitation, I offer these pages for some good information :
This is Iomega's website, and offers some specific Zip parallel port information. Generally pretty good, but from an Iomega perspective :
This is a third parties page, but from someone that has used these drives quite often. It has a "from the field" perspective on these drives, and how to troubleshoot around them.
Finally, the download page from Iomega's website. You can "pluck" the latest drivers here at any time: