The Mac version of Outlook certainly doesn't make any of this much easier, what with formats like OLM! So much so that there are more than a few vendors of OLM to PST conversion software.
I decided to write this up because it still seemed like a largely unanswered question out there. I specifically did this for migrating data up to Google Apps, but having done similar things for my own personal Google account, I don't believe there's much difference.
This is not flawless by any means, so please don't do this with your eyes closed -) Do pay attention to the warning about uploading duplicate entries in Google.
This is what I found for doing it 'on the cheap'.
