I wrote this blog post a long time ago regarding Microsoft's Project viewer.
Today I found a much better solution. It's called Zamzar and it's a free file conversion service.
Microsoft Project, Microsoft Publisher, Word, and many others. And it works. I used it to convert a Publisher document to PDF and the results were very good.
Highly recommended solution to the ever pesky problem of dealing with file formats when you don't have the native app required to view it.