In Reply to: You don't posted by tsking on Sunday, 24. February 2008 at 15:06 Bali Time:
Before you ask to have international roaming installed on your phone check on the costs associated with that.
You will be charged for not only making calls, but also for receiving calls on your mobile.
For ease of mind I would be doing as others have suggested and taking an unlocked phone with you and purchasing a local sim card with local number. Works out alot less expensive than international roaming.