Christians in Beijing

When I was just a lad and growing up in America, I learned that Christianity was taboo in communist China. Is it still the same today, with "underground" church services or is it more public and open? Are there any Christian groups or churches that expats could join? I will be moving to BJ in two weeks and that is one thing that I would love to find right off the bat! If anyone could shine the light on the subject for me that would be great; even Christian dating would be a plus too.
Thanks,
Marty