Add google font

I want to add a google font, such as Cabin Sketch. I can find the font in the google web fonts directory (http://www.google.com/webfonts) but NOT in the list (template manager / ... / fonts). How can I add this font to the list so as to be able to select it?

Thank you

in Joomla 1.5: search in templatefolder admingooglefonts.php and add the font you want.