1) File->Import
Link to the .pub file within the web. Users will need a copy of
Publisher to open the file.
2) (Best) Convert the file to .pdf, and import/link to the .pdf file.
3) (worst) Save the document as HTML, and import the HTML file and
associated folder. HTML files produced by Publisher are best
described as atrocious.
4) Reproduce the publisher document in FrontPage, starting from
scratch.