Super low-tech, but I just email the MS to my Gmail every so often. Then I can get it from anywhere.
Dropbox.
If you can install it on both computers, just save the files like you would regularly, but within the Dropbox folder, and they'll automatically get uploaded to the cloud for backup and also synced between both of your computers.
If you can only install it on one (e.g. locked down work computer), then at least you'll only have to manually retrieve and upload it when you work on one of them, and on the other computer you can work without having to worry about it, and it'll backup to the cloud automatically.
If I know I'm going to be traveling, I upload to SkyDrive on my Hotmail account. Beats emailing to myself as I have thousands of emails which one day I'll clear out...
Dropbox here too. I don't even have to remember to save. I also email to myself with finished pieces.