Take a look at
www.synchpst.com. I believe this link was posted a few weeks back. I haven't tried it yet but am considering using it to sync up my laptop and tablet.
For now I just copy my pst file to my tablet and then don't bother adding or saving any e-mails (I only download copies to the tablet). Any e-mail I do send, I copy to myself. Usually I am only away with the tablet for a day or two at most so this is not that much of a bother.
I know I could copy the pst file back to the laptop upon my return to the office, but as my outlook.pst file is almost as important as that thing in my chest that goes, thump...thump...thump, I don't want to mess with it too much.