Australian citizen visitor in the US, how can I apply for a chinese visa? Is it possible through HK?

I am currently in the UK as a visitor but will be in the US under the VWP for the next 2 months. I need to go to China for end of June, how can I obtain one? I heard it won't be possible in the US as I'm only a visitor and not a resident. Also seen it might be possible to apply in a day or so if I stop over in HK?