That's right, onewrite.
In fact saving back to MSPub2000 might not be enough. It may be necessary to actually open the saved-back file in MSPub2000 and re-saved using MSPub2000.
Assuming that you can convert the MSPub file, you will still need to do a lot of work to get the file into some sort of order. Remember MSPub users often use metafiles and Insert Object (e.g. WordArt), neither of which sit happily with PM. However, there probably won't be a font problem unless you have uninstalled Jokerman and Comic Sans!
Many people end up recreating the document by importing the (raw) text and re-formating the images to TIFF or EPS using PhS or Illustrator/Corel Draw.
Iechyd da! John
Glannau Mersi, Lloegr.