The easiest way is to opne the web page in Expression Web, click on a word you want to identify the font for then look in the CSS Properties Task Pane. Go up the list of styles applied until you see the font specified then right click on that element and select "go to code" which will take you to the individual style in the stylesheetthat is controling the font.
Cheryl D Wise MS MVP Expression Instructor: starttoweb.com