<html> <body> <head> <style type="text/css"> @import url(/css/style.css); </style> </head> </body> </html>
But not all browsers support @import. I wanted to see exactly which ones didn't so I used browsershots.org with a simple test.
Here are the results: http://browsershots.org/http://volatileminds.net/import_test.html
Black means it supports it. White means it doesn't.