Mobile Telephone
There are two good service providers China Mobile and China Unicom. You can get both pre-paid and monthly billed accounts with them.
To register for billed accounts take passport and a local person with ID card to register. A monthly 60rmb is charged for SIMM card usage. 
To get a pre-paid card go to any convenience store or newspaper stand to buy one. Top up card are available at convenience store, subway counters and newspaper stands
http://www.chinamobile.com/en/
http://www.chinaunicom.com.hk/en/home/default.html