Use the following instructions:
1.
Install the getdeb package.
2.
Or configure the repository manually:
Go to System-Administration-Software Sources, Third-Party Software tab, Add:
deb
http://archive.getdeb.net/ubuntu natty-getdeb apps
Add the repository GPG key, open a terminal window and type:
wget -q -O-
http://archive.getdeb.net/getdeb-archive.key | sudo apt-key add -
3.
Click the "Install this now" button below the screenshot of the desired application.
4.
If you are using Kubuntu please check bug 476853.