I was notified today of a free on-line service that looks interesting: A free Microsoft Publisher to PDF conversion service. See publishertopdf.com.
I haven't tried this, but am keeping a link to it for the couple-of-times-year occasion when someone sends me a Microsoft Publisher file that I need to either just look at, or worse, convert to InDesign.
A few related links:
More free online file conversions: Cometdocs
Recosoft PDF2ID to convert PDF and XPS files to InDesign.
Markzware PUB2ID to convert Publisher to InDesign files.
Markzware PDF2DTP to edit PDF in InDesign or QuarkXPress.