There’s a few different ways to install the Google Web fonts on your Ubuntu system. Web UPD8 provides a script that does it for you.
Another way is to use TypeCatcher, as suggested by Jack Wallen at TechRepublic. You can install TypeCatcher via a PPA, which means easy updates. No auto-updates with the script method, unfortunately.
To install TypeCatcher via PPA, open a terminal and run sudo add-apt-repository ppa:andrewsomething/typecatcher and then run sudo apt-get update && sudo apt-get install typecatcher. That’s it, TypeCatcher should show up in your applications menu. If you’re using Xubuntu, it’s under Accessories.
I’d never heard of TypeCatcher until I came across Jack’s post at TechRepublic. Installed it on Xubuntu 13.10 and fell in love with it. Just select a font, and click the install button, done. The featured image for this post is TypeCatcher with the Lato font selected. For more details on TypeCatcher, go read Jack’s post.
If you can’t use a PPA, or don’t want to, you’ve still got a good option for easily installing the fonts with the script from Web UPD8. If you’d like to see how the script works, you can download it here. It essentially just using Mercurial to install them.