FYI, there is currently a y80/month Unicom data plan (3 month min, but it's pretty easy to pick up cards that are midway through the cycle and sell yours when you leave) that includes 3g/month in your local area and 100m roaming. IME, the 100m roaming is sufficient for most travelers, as long as you stick to web surfing and email only (and refrain from downloading large attachments).