In OS X versions prior to 10.5, if you wanted to preview a font, you had only a couple of choices: you could view it in Font Book, or in an application that supported some form of font previews. In Leopard, though, there are at least three new ways.
Apple Day – Apple, iPod, iPad, iPhone, iTouch, iMac, iBook
Apple Day – Apple, iPod, iPad, iPhone, iTouch, iMac, iBook