Converting embedded CSS to inline CSS for mail()?

I've tried sending HTML mail with embedded CSS, that is, CSS that is defined between STYLE tags located in the HEAD of the HTML. However, some e-mail clients, esp. Outlook, don't recognize the CSS.

In order to force crappy Outlook to recognize CSS, I need to use inline CSS.

I really want to keep my CSS defined together by the embedded method since it is easier to modify CSS located in one central source to affect many HTML elements, not by the tedious inline method. Is there a way to force Outlook to recognize my CSS (other than using a link)?

If not, is there a PHP function which can accept a file defining embedded CSS styles and parse a HTML file such that a new file is spat out with the CSS inserted inline? I am thinking about writing a function, but jeez, what a pain when it comes to nested CSS definitions.

Thanks.