I found out this document converter trying to help Ming
convert some very old MacWrite II files.

http://www.soconverter.com/soc.nsf/webpages/fileformats_e.htm

I've converted some old files going back to 1990 successfully,
though I had some problems with MacWrite Pro files. If you have
problems, try using the default extensions in the above link.

Here are some additional converters if you don't like PDF:

http://www.smashingmagazine.com/2007/04/10/online-converters/