net working is the best way by far.The only reason I am not working in Beijing right now is that the enviroment is better for my kids in Australia.and this job came about through knowing the right people

Not all of the top vacancies come this way. However, multinational companies are hardly likely to be using a forum like echinacities or other common job boards. Your next best bet is probably www.linkedin.com and the there are numerous agencies or headhunting companies. The problem that you may face is that these very well paid executive positions held by expats are often filled overseas then by relocation into China. Sometimes you can drop lucky and find one locally.

I agree with Kaiwen. I often see job ads for senior-level positions advertised on linkedin. It's for more serious jobs whereas the opportunities posted on local job sites are often not really long-term career jobs. They're just stepping stones. Networking, as philbravery mentioned, is also key to getting the good jobs. I would also sign up to various google groups, get job alerts from companies' websites and sign up for various job related newsletters.