I would like to know how to do this as well, but I would be even more interested in being able to easily dump notes and then move them to a remote service like Google Note.

If you don't need to sync two profiles (as on that thread) and just need to move from one computer to another, overwriting what's on the second one, the easiest thing to do at the moment is just to copy the entire 'zotero' directory within your Firefox profile directory (e.g. C:\Documents and Settings\<your username>\Application Data\Mozilla\Firefox\Profiles\<random string>\zotero on Windows or /Users/<username>/Library/Application Support/Firefox/Profiles/<random string>/zotero on OS X) to a portable drive (or zip the folder and send it via e-mail) and then copy it to the Firefox profile directory on the other computer. After installing Zotero on the second computer, Zotero should automatically use the copied data. (If you've run Zotero on the second computer before, you'll want to remove the existing 'zotero' directory first, assuming there's no data you care about there.)

Note that linked files won't be accessible on the new computer, as they're stored elsewhere on the old computer. Imported files and snapshots won't work in 1.0.0b2.r2 on the new computer, but they should work if you wait until Beta 3 is out (should be within a week) before making the switch.