You might want to elaborate on what you mean by “bilingual.” If you want the kids to be able to speak like three-year-olds in China it should be simple enough: just have the native speaker (your wife) exclusively speak to the baby in Chinese from day one. The native English speaker, likewise, should use only English. That will keep a clear separation in the child’s mind. As the child gets older, however, if your goal is that you could pack up and move to China at any time and have the high school aged child function in a Chinese high school (at least in terms of the language) then you would really have to have a more thought out program. (Chinese housekeeper, bilingual preschool, immersion elementary school, weekend classes, etc.).
One final thought regarding the newborn: try to make as many routine activities ones that are experienced in both languages. You can start a library of children’s books in Chinese so that your wife can read stories to the baby in Chinese. When its your turn you can read from English language books.
And a final final thought about the long term goal of bilingualism: When the kid gets to the point of wanting to “fit in” with American peers they may quickly lose interest in being “special” because of being bilingual. Don’t be surprised if the kid is embarrassed when mom comes to school and speaks in Chinese. I have also noticed that the attrition rate for weekend Chinese schools is very high. It’s hard to keep a high school student motivated to do yet one more day of school during the week, and extra study. You will have to decide by then how much extra stress you are willing to tolerate in your lives in order to maintain this goal of bilingualism.