From Pages '09, you can see WYSIWYG font previews in the Format Bar font menu. Just make sure that you have the preferences right: Pages > Preferences > Show font preview in Format Bar font menu. To switch between WYSIWYG and standard font names, hold down the alt-key, as you click on the menu.
In previous versions this was not possible, but there were some other options that worked fairly well - some would say better.
Use the Font palette header
Follow these steps:
- Display the Font palette using ⌘-T or the menu Format > Fonts > Show Fonts.
- Click on the wheel in the lower left corner and choose "Show Preview".
You will get a preview of the currently highlighted font.
To easily scroll between the fonts, first put your cursor in the search field. This will take the focus away from your main document. Then highlight a font and scroll up and down with the arrow keys.
Use the Font palette Favorites

Select the collection "Favorites". It lists the latest font families you used, and it shows them in the last used Typeface and Size.
Use an Apple Script
Follow these steps:
- In the Finder, go to Applications and open Font Book.
- In Font Book, highlight all fonts (or the ones you are curious about).
- In the Finder, go to Applications > AppleScript > Example Scripts > Font Book and double click on Create Font Sample.scpt. It will open in Script Editor.
- In Script Editor click on "Run".
- Wait.
After some time, you will have a document in TextEdit that contains samples of all your Typefaces in all your fonts. Save it for future reference.
Use Font Book

Font Book is an important tool for at least two purposes. One - display what your fonts look like. Two -
organise your fonts.
The main reason Apple has not included WYSIWYG font displays in Pages or the Font Palette is that it would be next to impossible with all the fonts we have today. You would have to scroll for ever - up and down, looking for a font that fits your needs. You would forget the name of one you saw and you would have to start over again.
WYSIWYG font menus worked on the first Macs, when the average user had no more than six fonts, but today the average user has several hundreds.
If you are serious about finding the most perfect font in this hay stack, use Font Book collections. It does not cost anything, and they are easy to remove, when no longer needed.
Create a collection for for example sans serif fonts, another for good body text fonts, another for Chinese fonts, and so on. It will be much easier to compare Monaco and Andale Mono, if they are in the same small collection, than if you have to scroll 150 fonts to get from one to the other. For more hints how to create collections, check
this post.