Interim Management in China?'

I've been offered an assignment in Beijing through a BPR consultancy here in DC. They don't have much information on what visa I will need and the tax implications for my US tax return. Can you help?
Contractor Taxation Vocabulary: 

We've got several sponsorship providers who specialise in just this area. They will get you a work / Z visa, residents permit, employment contract and ensure you are fully compliant from an employment and immigration perspective. Additionally they can payroll you, process your expenses and file your tax returns - so you are tax compliant as well. We also have a partnership with a specialist US tax advisor registered to practice with the IRS who is highly experienced in dual taxation for American expatriates. Alternatively they can advise your consulting company on how to do this.