OLD METHOD

To make a local copy of the package selection:

dpkg –get-selections >myselections

You might transfer this file to another computer, and install it there with:

dpkg –clear-selections dpkg –set-selections

Now (If subscribed to Ubuntu One Cloud):

In Ubuntu 11.10, open the Software Center and navigate to “File>Sync Between Computers” you can see each machine hooked up and manually install the missing apps yourself. But before that you have to set up the ubuntu sync.

Note: The above method works on all Debian based systems.