The text is Lucida Grande an easy way I use to find out is just copy a chunk of the text into Word. As the formatting is maintained. Then you can see the font very easily.
That's a great and easy tip !
I assume it also works with pages..
And my Lucida Grande created text does not looked good because of the way fireworks renders text, when I clicked on "preview in Safari" on fireworks the text doesn't look very good, so I tried with Flash and clicked on "preview in browser" and the text look great!