As of right now, there is no cloud syncing, and I'm not sure what the future holds. I think there's been some rumblings about this at some point.
For now there are several ways to do it:
1. Brainzip your data and then transfer it to the other computer prior to working on it again. This is recommended by folks at TheBrain. The main downside is it's slow, and easy to forget to do. If you do this, make sure to check the Search Index box when you do it. It means PB doesn't have to rebuild your index each time you restore your data on the machine, and is a huge timesaver.
2. Run your database off a USB drive. Depending on the speed of your USB drive, it can cause a noticeable hit to performance. However, it does mean you can just pop the stick in, and start PB.
3. Use a third party cloud syncing solution (I use DropBox). Folks from TheBrain do not endorse or recommend this solution, and you run a greater chance of corrupting your database by doing so. We have had several forum members who have had their database corrupted, so use at your own risk. For instructions on how to do it, search the forum, or I've posted the steps I follow here. I've been syncing using this procedure for over a year now without issue, but I have to be diligent about following the steps, and I make daily backups.
Java SE 6