I use CSSEdit from MacRabbit. It gives you realtime feedback of every thing in CSS 2.1, not just typography. If you embed a bunch of google fonts into an HTML page, and then load it in CSSEdit, you'll be able to use all those fonts. Use an external HTML editor to edit and mark up the text, and use CSSEdit to play with the styles in real-time.
Reminder: CSS can not do everything that a program like Indesign can do for typography. No Hyphenation, no automatic multi-column layouts, etc.