A debian package for TurtleArt is now available for Ubuntu. The launchpad site has information on how to install it on the upcoming 10.04 (Lucid) release of Ubuntu is on the site, but for the command line comfortable, the simplest solution is to run each of the following command in a terminal (in order):
sudo add-apt-repository ppa:mattva01/ppa
sudo apt-get update
sudo apt-get install turtleart
I just finished running these steps for the 3rd time, and they worked each time, with the following warning:
install-info: warning: no info dir entry in `/usr/share/info/activity.info.gz'
I can't figure out how to file bugs on launchpad, and plan to follow up on that next.
In addition to the warning mentioned above, there is no icon yet for the Applications -> Education -> TurtleArt menu item. I'll ask TurtleArt developer Walter Bender what he thinks about the icon later today.