The PRC generally does not recognize International Driving Permits and does not permit foreigners to drive in China without a Chinese license. Note that Hong Kong and Macau licenses are also considered to be foreign and having one of them will not allow you to drive in the mainland. This supposedly changed in 2007 and short-term driving without a Chinese license became legal. However, as with many laws in China, official changes and changes in practice do not necessarily correspond; as of December 2008 it is still illegal for foreigners to drive without a Chinese license. Unless you have diplomatic status, importing foreign vehicles is very costly.
Rented cars most often come with a driver and this is probably the best way to travel in China by car. Driving in China is not recommended unless you are used to extremely chaotic driving conditions. Traffic moves on the right in mainland China.
English directional signs are ubiquitous in Beijing, Shanghai and other major cities which see many Western tourists. However, they are spotty at best in other cities and virtually non-existent in the countryside. As such, it is always a good idea to have your destination written in Chinese before you set off so that locals can point you in the right direction should you get lost.
Foreigners should really avoid driving outside of major cities. "One Way" signs usually mean "mostly but not always one way". Expect someone who misses an exit ramp on a freeway to slow down just before the upcoming entry ramp and make a 270° turn to engage on that ramp. Expect drivers to take creative shortcuts at traffic circles.
As a pedestrian ALWAYS look both ways every time you cross any street. Not only may a bicycle come along traveling in the wrong direction, so may increasingly popular electric motorbike -- and they are silent.