But in this day and age, I've found that a multiple computer lifestyle can work very easily using only free software.
The first two steps of this instructable tell you how to set up Dropbox, a great utility for synchronizing files. Step 2 has a bonus tip on a cheap but good looking netbook stand. Steps 3-6 cover additional tools and methods you can use to make your polycomputational lifestyle even better: OpenOffice.org, Google Notebook, the "sharing" feature of Dropbox, and Synergy, for sharing your keyboard and mouse wirelessly between the computers.
Step 1: Grab Dropbox
You'll then want to download the Dropbox client. Downloads for Mac OS X, Windows, and Ubuntu can be found on the Dropbox homepage. My Eee runs Debian, but a quick trip to Google showed that, with the magic of free software, that was no problem at all. This site has instructions on how to get the client for Debian.
Now that you've got the client, let's make some folders.