[seanmcdirmid]

Huh? They have a booth selling China mobile SIMs, but they might offer Unicom also (important if you have a GSM phone) inside customs, I believe it is 24 hours, for most international airports.

The SIM is pay as you go, you can refill it at most newspaper stands.

[cushychicken]

The problem generally isn't the SIM itself - it's the form factor. Granted I haven't traveled to China in two years now, but MicroSIM form factor was nonexistent there on my last trip. Many vendors used cheap, shitty handheld punches to get the excess plastic off of normal SIM cards to get them into SIM form factor. This worked about one time out of five - most of the time it just destroyed the SIM card.