The Scratch Team have setup a repository on launchpad with the latest version for Ubuntu. Here are some quick instructions for Ubuntu Karmic Koala (9.10) and Jaunty (9.04).

1. Open Synaptic Package Manager from the System > Administration.
2. From the Package menu, select Software Sources.
3. From the Software Sources dialog box, click on the Other Software tab and click Add…
4. If you’re a Karmic Koala user, add the following repository when prompted:

    deb http://ppa.launchpad.net/scratch/ppa/ubuntu karmic main

   Click Add… again to enter the source repository:

   deb-src http://ppa.launchpad.net/scratch/ppa/ubuntu karmic main

5. If you use Jaunty (9.04) substitute these sources:

   deb http://ppa.launchpad.net/scratch/ppa/ubuntu jaunty main

   deb-src http://ppa.launchpad.net/scratch/ppa/ubuntu jaunty main

   

6. Click the Close button to close the software sources. You may be prompted that your repositories changes. Acknowledge the message.
7. Reload your package information by clicking the Reload button in Synaptic Package Manager.

You can now search for “scratch” in Synaptic Package Manager and install Scratch as any other Ubuntu app. And now when the Scratch team updates the package, you can update with Ubuntu’s package management system.