Pointing to externaly hosted style.css

Hey,

I’m using a css site theme and matching wordpress theme from http://www.freecsstemplates.org. I would like to only have to maintain one style file. The style files are identical.

Does any one know how to modify a theme so that it uses a style sheet hosted else ware than inside the theme file?
Lets call the main site http://www.example.com, and its main style sheat is at http://www.example.com/style.css (the one I would like to use everywhere). The blog would be located at blog.example.com

Thanks in advance!