How do I access to the websites in China?

My ISP is SBC or AT&T( I forget which is the right one.) And I live in Alameda, CA. In the past week, I couldn't access any of the website in mainland china(except those in Taiwan and Hong Kong.) I thought this was my computer problem at first. But I asked my friend who live in Concord, CA (25 miles from Alameda) if he has the same problem, and the answer is yes. So, does any one know what happen to the internet connection to china in the Bay Area?