How can I view a Microsoft Publisher .pub file?

I don't know of any applications that do this but, you can use this to convert PUB files to PDF. An alternative would be to install Microsoft Publisher through Wine (available in the repositories).

In case anyone runs into this question, a Microsoft Publisher importer is expected in LibreOffice 3.7. More info:

http://libregraphicsworld.org/blog/entry/microsoft-publisher-support-makes-its-way-to-libreoffice http://fridrich.blogspot.ch/2012/06/libreoffice-ms-publisher-import-filter.html

I spent a long time investigating this recently as I needed to index .pub files for use in Xapian.

The conclusion is that the only thing that can read .pub files is publisher.

You can run publisher in CrossOver Office with some success. I have used this in the past and I had no problems.