I have done this...and it was ugly. Had to read some really bad english and try to figure out what I was supposed to do. Plus I lost all of my attachments. (Stupid Perl script that only extracted text
)
Anywho, there seem to be some better options now. SourceForge has a project for a program that will convert .pst files to the unix standard mbox, which can be imported in Mail 1.2.2 or Entourage (if you only have OS X.1) and then you can import from Entourage to mail.
Here is the link
http://sourceforge.net/projects/ol2mbox/
I have aslo heard that you can use Mozilla's mail (on your windows box) to import from the .pst file and export to mbox. I haven't tried that yet, but every windows box could use Mozilla, so even if it doesn't work, it is still worth the download.
If you search the internet for outlook to unix, you will find a great deal of websites that mention installing an IMAP server on your unix box (aka Mac) and then move your messages that way...but that is way to complicated for me.