Paul, I'm really looking forward to your formulas!
However, those of us on Linux can't work with 'Works'. (Here would normally follow many sentences of grandstanding about "supporting criminal monopolists" and etc... Let me just say that I
strongly recommend openoffice.org to my Windows customers too, and skip the rest.)
Neither openoffice.org nor koffice has bothered to spend their S/W Development time on "import" of .wks worksheets. They have good compatibility with xls. I don't know about other Office Packages, these are the two which I use and support with a little Q/A from time to time.
Thanks in advance