The MB charger definitely supports 210/220V. You'll have to look on the LC-E5 charger, and make sure it says 110/220V or something in that neighborhood (110 may be 108-120, 220 may be 210-240).
Then you'll just need prong adapters like ^ said, from any electronic shop. From Wiki, it seems China uses a couple different plug types, maybe varying by age. These two should be this type in China: http://en.wikipedia.org/wiki/File:Chinasocket.jpg
In some areas, you may even find 2-pring USA style outlets for 220V in China, but those are ungrounded and I wouldn't be too thrilled about that.
I just came back from Beijing and my hotel (Dong Fang Hotel) had the 2-prong outlets available. The macbook charger (without extension cord) is ungrounded as well (2-prong) so that doesn't even matter.
Most hotels have the US style plugs. Outside of hotels you can just buy a converter. I would get a universal converter, can come pretty handy especially at airports.
Thank you all - for the most part I won't be staying in a hotel, so I guess I'll buy a converter, or conserve battery life as long as possible until I get to a hotel! 🙂
EDIT: Oh, and for the LC-E5 charger it says 100-240V, so it should be fine with the voltage, I guess.
There are many imported electronics from North America in China that came with our 2-prong plugs. You should be able to easily find an adapter in local hardware stores.