Thanks Dave. :icon_biggrin:
Shuan, sim cards are locked to the phone company that issues them because that's how the phone number is entered into the system. As Dave said, you want an unlocked GSM phone if you want to take it to China. I'm sure you could pick one up in your local TigerDirect or Overstock or Newegg... But make sure it's a quad-band phone (it will operate on 4 frequencies) as China may use different frequencies than they use in the US. The phones need to be unlocked because many of the phone companies like AT&T or Verison lock the phone down with software so they can't accept a sim card from their competitors (otherwise they wouldn't subsidize the phone on a contract)
What a lot of people do is if they're staying in a region for any extended period of time, they'll just pick up a sim card from the local phone company. I suggested to Dave he do that in Singapore as it'll be cheaper than using his phone there (assuming he's got a Rogers/Fido phone).
I know many of the ladies I have talked to in China switch sim cards/phone numbers on a regular basis depending on where they will be staying as the benefits change.
