Did you know that if you declare a custom font using @font-face, the browser will try to fake the bold and italic styles if it can’t find them? This is a clever little feature that avoids a scenario where a themer specifies a font and is then confused that bold and italics don’t work, but it can be very confusing if you actually have a bold or italic version of the font. In this article, I’ll walk you through how to properly load your font files to avoid the browser’s faux-italic and faux-bold styles.
http://www.metaltoad.com/blog/how-use-font-face-avoid-faux-italic-and-bold-browser-styles
http://oscorp.net/projects/font-face/