That handset supports GSM900 so would work everywhere in Thailand on many networks, and in other parts of SE Asia. I can't remember if China is GSM900 everywhere, but am pretty sure it is, along with some CDMA networks maybe.

However, it is not clear to me that this phone actually has a GPRS modem. It has basic GPRS connectivity to allow internet access on the phone's tiny screen. As far as I can determine it does not have a GPRS modem, which would allow you to use it for PC/Internet connectivity as we've been discussing.