In Reply to: iphone for internet posted by kenb on Tuesday, 2. February 2010 at 21:36 Bali Time:
Going to be using mine in May, reading this with interest.
From what I understand if you turn Data roaming off - settings, general, network,then it wont try to roam and will not incur any charges when using local wifi.
I will be using a local sim though and taking my optus sim out, so no chance anyway of racking up any data charges.
Make sure you unlock from your carrier before you go if you want to use a local sim, and remember that with the iPhone once the carrier has unlocked it you still need to backup and restore through itunes before the unlock takes effect.